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IdentificationPharmacologyInteractionsReferencesTrialsEconomicsPropertiesSpectraTaxonomyDiphenhydramine
Identification
- Name
- Diphenhydramine
- Accession Number
- DB01075 (APRD00587, DB06975)
- Type
- Small Molecule
- Groups
- Approved, Investigational
- Description
Diphenhydramine, also known commercially as Benadryl, is a first generation antihistamine that is used primarily for the treatment of seasonal allergies. However, it also has antiemetic, antitussive, hypnotic, and antiparkinson properties. As histamine receptors exist both peripherally and in the central nervous system, diphenhydramine has been shown to cause sedation due to its competitive antagonism of histamine H1 receptors within the central nervous system. While its use in in allergies has largely fallen out of favour due to this sedative effect, diphenhydramine has been repurposed for use within many OTC (over the counter) cough-and-cold medications that have been marketed for "night time" use.
Diphenhydramine is also used in combination with 8-chlorotheophylline as the anti-nausea drug Dimenhydrinate where it is utilized primarily for its antagonism of H1 histamine receptors within the vestibular system [4].
Diphenhydramine has also been shown to be implicated in a number of neurotransmitter systems that affect behaviour including dopamine, norepinephrine, serotonin, acetylcholine, and opioid [3]. As a result, diphenhydramine is being investigated for its anxiolytic and anti-depressant properties.
- Structure
Structure for DB01075 (Diphenhydramine)
- Synonyms
- 2-(Benzhydryloxy)-N,N-dimethylethylamine
- 2-diphenylmethoxy-N,N-demthylethanamine
- alpha-(2-Dimethylaminoethoxy)diphenylmethane
- beta-Dimethylaminoethanol diphenylmethyl ether
- beta-Dimethylaminoethyl benzhydryl ether
- Difenhidramina
- Diphenhydraminum
- N-(2-(Diphenylmethoxy)ethyl)-N,N-dimethylamine
- O-benzhydryldimethylaminoethanol
- β-dimethylaminoethyl benzhydryl ether
- Product Ingredients
Ingredient UNII CAS InChI Key Diphenhydramine citrate 4OD433S209 88637-37-0 SPCKHVPPRJWQRZ-UHFFFAOYSA-N Diphenhydramine hydrochloride TC2D6JAD40 147-24-0 PCHPORCSPXIHLZ-UHFFFAOYSA-N Diphenhydramine methylbromide UJO67AO8YI 31065-89-1 BDQPXVWYFLTETB-UHFFFAOYSA-M Diphenhydramine salicylate 707L3YC54L 7491-10-3 RTSZUSOHOIFYSY-UHFFFAOYSA-N - Product Images
- Prescription Products
Name Dosage Strength Route Labeller Marketing Start Marketing End Benadryl Inj. 50mg/ml Liquid 50 mg Intramuscular; Intravenous Warner Lambert Canada Inc. 1994-12-31 2000-11-27 Canada 
Diphenhydramine HCl Inj USP 50mg/ml Liquid 50 mg Intravenous International Medication Systems, Limited 1974-12-31 1997-08-15 Canada Diphenhydramine HCl Injection, USP Solution 50 mg Intramuscular; Intravenous Sterimax Inc 1994-12-31 Not applicable Canada Diphenhydramine Hydrochloride Injection Solution 50 mg Intramuscular; Intravenous Fresenius Kabi 2012-02-17 Not applicable Canada Diphenhydramine Hydrochloride Injection USP Liquid 50 mg Intramuscular; Intravenous Sandoz Canada Incorporated 1983-12-31 Not applicable Canada Diphenist 50mg/ml Liquid 50 mg Intramuscular; Intravenous Omega Laboratories Ltd 1997-10-28 Not applicable Canada Scheinpharm Diphenhydramine Inj.50mg/ml Solution 50 mg Intramuscular; Intravenous Schein Pharmaceutical Canada Inc. 1996-09-30 2004-07-26 Canada - Generic Prescription Products
Name Dosage Strength Route Labeller Marketing Start Marketing End Diphendydramine Hydrochloride Capsule 25 mg/1 Oral Remedy Repack 2010-12-17 2017-06-20 US 
Diphenhydramine Injection, solution 50 mg/mL Intravenous Remedy Repack 2013-06-13 2017-01-24 US Diphenhydramine Injection, solution 50 mg/mL Intramuscular; Intravenous APP Pharmaceuticals, Inc. 2002-08-01 Not applicable US Diphenhydramine Hydrochloride Injection 50 mg/mL Intramuscular; Intravenous Rebel Distributors 1972-11-27 Not applicable US Diphenhydramine Hydrochloride Injection 50 mg/mL Intramuscular; Intravenous West Ward Pharmaceutical 1972-11-27 Not applicable US Diphenhydramine Hydrochloride Injection 50 mg/mL Intramuscular; Intravenous Sina Health Inc 1972-11-27 Not applicable US Diphenhydramine Hydrochloride Elixir 25 mg/10mL Oral Cardinal Health 1982-02-10 2018-07-10 US Diphenhydramine Hydrochloride Injection, solution 50 mg/mL Intramuscular; Intravenous General Injectables & Vaccines 2017-06-13 Not applicable US Diphenhydramine Hydrochloride Injection 50 mg/mL Intramuscular; Intravenous Dispensing Solutions, Inc. 1972-11-27 Not applicable US Diphenhydramine Hydrochloride Injection 50 mg/mL Intramuscular; Intravenous Remedy Repack 2018-03-29 Not applicable US - Over the Counter Products
Name Dosage Strength Route Labeller Marketing Start Marketing End 7 Select Allergy Tablet 25 mg/1 Oral 7 Eleven 2014-04-22 Not applicable US 7 Select Allergy Childrens Solution 12.5 mg/5mL Oral 7 Eleven 2014-08-05 Not applicable US 7 Select Night Time Sleep Aid Solution 50 mg/30mL Oral 7 Eleven 2014-04-22 Not applicable US Adult Allergy Solution 50 mg/20mL Oral Chain Drug Consortium 2015-05-04 Not applicable US Adult Allergy Relief Solution 50 mg/20mL Oral Walmart Stores 2017-05-03 Not applicable US After Bite Outdoor Gel 20 mg/g Topical Tender Corporation 2018-03-01 Not applicable US After Bite Outdoor Gel 20 mg/mL Topical Tender Corporation 2016-11-01 2018-03-08 US After Bite Plus Gel 20 mg/g Topical Tender Corporation 2018-03-01 Not applicable US After Bite Plus Cream 20 mg/mL Topical Tender Corporation 2012-07-03 2018-03-08 US After Bite Xtra Gel 20 mg/mL Topical Tender Corporation 2016-11-01 2018-03-08 US - Mixture Products
Name Ingredients Dosage Route Labeller Marketing Start Marketing End 7 Select Ibuprofen PM Diphenhydramine citrate (38 mg/1) + Ibuprofen (200 mg/1) Tablet, film coated Oral 7 Eleven 2014-08-05 Not applicable US 7 Select Night Time Severe Cold Cough and Flu Diphenhydramine hydrochloride (25 mg/1) + Acetaminophen (650 mg/1) + Phenylephrine hydrochloride (10 mg/1) Powder, for solution Oral 7 Eleven 2016-01-25 Not applicable US 7 Select Night Time severe cold, cough and flu Diphenhydramine hydrochloride (25 mg/1) + Acetaminophen (650 mg/1) + Phenylephrine hydrochloride (10 mg/1) Powder, for solution Oral 7 Eleven 2015-11-12 2018-03-29 US 7 Select Pain Relief PM Diphenhydramine hydrochloride (25 mg/1) + Acetaminophen (500 mg/1) Tablet, film coated Oral 7 Eleven 2014-09-04 2017-11-22 US 7-Select Advil PM Diphenhydramine citrate (38 mg/1) + Ibuprofen (200 mg/1) Tablet, coated Oral Lil' Drug Store Products, Inc. 2011-06-01 2017-12-31 US Aceta-gesic Diphenhydramine hydrochloride (12.5 mg/1) + Acetaminophen (325 mg/1) Tablet, coated Oral Remedy Repack 2014-08-08 Not applicable US Aceta-gesic Diphenhydramine hydrochloride (12.5 mg/1) + Acetaminophen (325 mg/1) Tablet, coated Oral Rugby 2014-06-30 Not applicable US Acetadryl Diphenhydramine hydrochloride (25 mg/1) + Acetaminophen (500 mg/1) Tablet, film coated Oral Physicians Science & Nature Inc. 2011-07-21 2017-11-30 US Acetadryl Diphenhydramine hydrochloride (25 mg/1) + Acetaminophen (500 mg/1) Tablet, film coated Oral Aidarex Pharmaceuticals LLC 2011-07-21 Not applicable US Acetaminophen / Diphenhydramine 500/25 mg Diphenhydramine hydrochloride (25 mg/1) + Acetaminophen (500 mg/1) Tablet Oral Reliable 1 Laboratories 2015-11-01 Not applicable US - Unapproved/Other Products
Name Ingredients Dosage Route Labeller Marketing Start Marketing End Airacof Diphenhydramine hydrochloride (12.5 mg/5mL) + Codeine phosphate (7.5 mg/5mL) + Phenylephrine hydrochloride (7.5 mg/5mL) Liquid Oral Centurion Labs 2010-01-08 2016-10-13 US Antiphlamine Coin Plaster Diphenhydramine (.246 mg/.2832g) + Camphor (1.108 mg/.2832g) + Menthol (2.769 mg/.2832g) Patch Topical Hanul Trading Co., Ltd. 2016-10-10 2017-02-11 US Antiphlamine Coin Plaster Diphenhydramine (.246 mg/.2832g) + DL-alpha-Tocopherol (.308 mg/.2832g) + Menthol (2.769 mg/.2832g) + Methyl salicylate (5.541 mg/.2832g) + Nonivamide (.046 mg/.2832g) + Peppermint oil (.693 mg/.2832g) + Synthetic Camphor (1.108 mg/.2832g) Patch Topical Hanul Trading Co., Ltd. 2016-10-10 Not applicable US Contrast Allergy PreMed Pack Diphenhydramine + Prednisone Kit Shertech Laboratories, Llc 2016-09-13 Not applicable US Dicopanol Diphenhydramine hydrochloride Kit Oral California Pharmaceuticals, Llc 2016-01-01 Not applicable US Dicopanol Diphenhydramine hydrochloride Kit Oral Fusion Pharmaceuticals LLC 2010-02-08 Not applicable US Diphenhydramine HCl Diphenhydramine hydrochloride (25 mg/1) Capsule Oral Cardinal Health 2011-06-03 2017-07-18 US Diphenhydramine HCl Diphenhydramine hydrochloride (25 mg/1) Tablet Oral Cardinal Health 2011-06-03 2018-05-31 US FIRST Dukes Mouthwash Compounding Diphenhydramine hydrochloride + Hydrocortisone + Nystatin Kit Oral Cutis Pharma, Inc. 2010-12-15 2017-10-04 US FIRST Marys Mouthwash Compounding Diphenhydramine hydrochloride + Hydrocortisone + Nystatin + Tetracycline hydrochloride Kit Oral Cutis Pharma, Inc. 2010-12-15 2017-10-04 US - International/Other Brands
- Aleryl / Alledryl / Allerdryl (Valeant) / Baramine / Beldin / Belix / Benylan (Biogen) / Dermodrin (Montavit) / Desentol (Meda) / Dibondrin (Montavit) / Dimedrol (Zdorovie) / Diphen (Wockhardt) / Dormarex 2 / Genahist / Histaxin (Meda) / Hyrexin (Hyrex) / Nytol Quickgels (GlaxoSmithKline) / Restamin (Kowa Souyaku) / Siladryl / Silphen Cough
- Categories
- Amines
- Aminoalkyl Ethers
- Anesthetics
- Anesthetics, Local
- Anti-Allergic Agents
- Anticholinergic Agents
- Antiemetics
- Antihistamines for Systemic Use
- Antihistamines for Topical Use
- Antipruritics, Incl. Antihistamines, Anesthetics, Etc.
- Autonomic Agents
- Benzene Derivatives
- Benzhydryl Compounds
- Central Nervous System Agents
- Central Nervous System Depressants
- Cytochrome P-450 CYP2D6 Inhibitors
- Cytochrome P-450 CYP2D6 Inhibitors (moderate)
- Cytochrome P-450 Enzyme Inhibitors
- Dermatologicals
- Ethanolamine Derivatives
- Ethylamines
- First Generation Antihistamines
- Gastrointestinal Agents
- Histamine Agents
- Histamine Antagonists
- Histamine H1 Antagonists
- Hypnotics and Sedatives
- Muscarinic Antagonists
- Neurotransmitter Agents
- OCT2 Inhibitors
- Peripheral Nervous System Agents
- Potential QTc-Prolonging Agents
- QTc Prolonging Agents
- Sensory System Agents
- Serotonergic Drugs Shown to Increase Risk of Serotonin Syndrome
- Sleep Aids, Pharmaceutical
- UNII
- 8GTS82S83M
- CAS number
- 58-73-1
- Weight
- Average: 255.3547
Monoisotopic: 255.162314299 - Chemical Formula
- C17H21NO
- InChI Key
- ZZVUWRFHKOJYTH-UHFFFAOYSA-N
- InChI
- InChI=1S/C17H21NO/c1-18(2)13-14-19-17(15-9-5-3-6-10-15)16-11-7-4-8-12-16/h3-12,17H,13-14H2,1-2H3
- IUPAC Name
- [2-(diphenylmethoxy)ethyl]dimethylamine
- SMILES
- CN(C)CCOC(C1=CC=CC=C1)C1=CC=CC=C1
Pharmacology
- Indication
For the treatment of symptoms associated with Vertigo/Meniere's disease, nausea and vomiting, motion sickness and insect bite.
- Associated Conditions
- Pharmacodynamics
Diphenhydramine is an antihistamine of the ethanolamine class. Ethanolamine antihistamines have significant antimuscarinic activity and produce marked sedation in most patients. In addition to the usual allergic symptoms, the drug also treats irritant cough and nausea, vomiting, and vertigo associated with motion sickness. It also is used commonly to treat drug-induced extrapyramidal symptoms as well as to treat mild cases of Parkinson's disease. Rather than preventing the release of histamine, as do cromolyn and nedocromil, diphenhydramine competes with free histamine for binding at HA-receptor sites. Diphenhydramine competitively antagonizes the effects of histamine on HA-receptors in the GI tract, uterus, large blood vessels, and bronchial muscle. Ethanolamine derivatives have greater anticholinergic activity than do other antihistamines, which probably accounts for the antidyskinetic action of diphenhydramine. This anticholinergic action appears to be due to a central antimuscarinic effect, which also may be responsible for its antiemetic effects, although the exact mechanism is unknown.
- Mechanism of action
Diphenhydramine competes with free histamine for binding at HA-receptor sites. This antagonizes the effects of histamine on HA-receptors, leading to a reduction of the negative symptoms brought on by histamine HA-receptor binding.
Target Actions Organism AHistamine H1 receptor antagonistHuman UMuscarinic acetylcholine receptor M2 antagonistHuman - Absorption
Quickly absorbed with maximum activity occurring in approximately one hour.
- Volume of distribution
- Not Available
- Protein binding
98 to 99%
- Metabolism
Hepatic and renal
- Route of elimination
Little, if any, is excreted unchanged in the urine; most appears as the degradation products of metabolic transformation in the liver, which are almost completely excreted within 24 hours.
- Half life
1-4 hours
- Clearance
- Not Available
- Toxicity
LD50=500 mg/kg (orally in rats). Considerable overdosage can lead to myocardial infarction (heart attack), serious ventricular dysrhythmias, coma and death.
- Affected organisms
- Humans and other mammals
- Pathways
Pathway Category Diphenhydramine H1-Antihistamine Action Drug action - Pharmacogenomic Effects/ADRs
- Not Available
Interactions
- Drug Interactions
Drug Interaction Drug group (2-benzhydryloxyethyl)diethyl-methylammonium iodide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with (2-benzhydryloxyethyl)diethyl-methylammonium iodide. Experimental 1,10-Phenanthroline The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with 1,10-Phenanthroline. Experimental 2,5-Dimethoxy-4-ethylamphetamine 2,5-Dimethoxy-4-ethylamphetamine may decrease the sedative and stimulatory activities of Diphenhydramine. Experimental, Illicit 2,5-Dimethoxy-4-ethylthioamphetamine 2,5-Dimethoxy-4-ethylthioamphetamine may decrease the sedative and stimulatory activities of Diphenhydramine. Experimental 3,4-Methylenedioxyamphetamine 3,4-Methylenedioxyamphetamine may decrease the sedative and stimulatory activities of Diphenhydramine. Experimental, Illicit 4-Bromo-2,5-dimethoxyamphetamine 4-Bromo-2,5-dimethoxyamphetamine may decrease the sedative and stimulatory activities of Diphenhydramine. Experimental, Illicit 4-Methoxyamphetamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with 4-Methoxyamphetamine. Experimental, Illicit 7-Nitroindazole The risk or severity of adverse effects can be increased when Diphenhydramine is combined with 7-Nitroindazole. Experimental 7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with 7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline. Experimental Abexinostat The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Abexinostat. Investigational Acebutolol The metabolism of Acebutolol can be decreased when combined with Diphenhydramine. Approved, Investigational Acepromazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Acepromazine. Approved, Vet Approved Aceprometazine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Aceprometazine. Approved Acetazolamide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Acetazolamide. Approved, Vet Approved Acetophenazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Acetophenazine. Approved Acetylglycinamide chloral hydrate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Acetylglycinamide chloral hydrate. Experimental Aclidinium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Aclidinium. Approved Acrivastine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Acrivastine. Approved Adinazolam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Adinazolam. Approved Adipiplon The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Adipiplon. Investigational Agmatine The serum concentration of Agmatine can be increased when it is combined with Diphenhydramine. Experimental, Investigational Agomelatine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Agomelatine. Approved, Investigational Ajulemic acid The risk or severity of Tachycardia and drowsiness can be increased when Diphenhydramine is combined with Ajulemic acid. Investigational Alaproclate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Alaproclate. Experimental Alcaftadine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Alcaftadine. Approved Alcuronium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Alcuronium. Experimental Alfaxalone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Alfaxalone. Vet Approved Alfentanil The risk or severity of adverse effects can be increased when Alfentanil is combined with Diphenhydramine. Approved, Illicit Alfuzosin The risk or severity of QTc prolongation can be increased when Alfuzosin is combined with Diphenhydramine. Approved, Investigational Alimemazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Alimemazine. Approved, Vet Approved Allobarbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Allobarbital. Experimental Allopregnanolone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Allopregnanolone. Investigational Alphacetylmethadol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Alphacetylmethadol. Experimental, Illicit Alphaprodine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Alphaprodine. Illicit Alprazolam The risk or severity of adverse effects can be increased when Alprazolam is combined with Diphenhydramine. Approved, Illicit, Investigational Alprenolol The metabolism of Alprenolol can be decreased when combined with Diphenhydramine. Approved, Withdrawn Amantadine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Amantadine. Approved Ambenonium The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Ambenonium. Approved Amifampridine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Amifampridine. Approved Amikacin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Amikacin. Approved, Investigational, Vet Approved Amineptine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Amineptine. Illicit, Withdrawn Amiodarone The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Amiodarone. Approved, Investigational Amisulpride The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Amisulpride. Approved, Investigational Amitriptyline The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Amitriptyline. Approved Amitriptylinoxide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Amitriptylinoxide. Approved, Investigational Amobarbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Amobarbital. Approved, Illicit Amodiaquine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Amodiaquine. Approved, Investigational Amoxapine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Amoxapine. Approved Amperozide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Amperozide. Experimental Amphetamine Amphetamine may decrease the sedative and stimulatory activities of Diphenhydramine. Approved, Illicit, Investigational Anagrelide The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Anagrelide. Approved Aniracetam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Aniracetam. Experimental Anisodamine The metabolism of Anisodamine can be decreased when combined with Diphenhydramine. Investigational Anisotropine Methylbromide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Anisotropine Methylbromide. Approved Antazoline The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Antazoline. Approved Apomorphine The risk or severity of QTc prolongation can be increased when Apomorphine is combined with Diphenhydramine. Approved, Investigational Apramycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Apramycin. Experimental, Vet Approved Aprobarbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Aprobarbital. Approved, Illicit Apronalide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Apronalide. Experimental Arbaclofen Placarbil The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Arbaclofen Placarbil. Investigational Arbekacin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Arbekacin. Approved, Investigational Arformoterol The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Arformoterol. Approved, Investigational Aripiprazole The serum concentration of Aripiprazole can be increased when it is combined with Diphenhydramine. Approved, Investigational Aripiprazole lauroxil The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Aripiprazole lauroxil. Approved, Investigational Arotinolol The metabolism of Arotinolol can be decreased when combined with Diphenhydramine. Investigational Arsenic trioxide The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Arsenic trioxide. Approved, Investigational Artemether The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Artemether. Approved Asenapine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Asenapine. Approved Astemizole The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Astemizole. Approved, Withdrawn Atazanavir The risk or severity of QTc prolongation can be increased when Atazanavir is combined with Diphenhydramine. Approved, Investigational Atenolol The metabolism of Atenolol can be decreased when combined with Diphenhydramine. Approved Atomoxetine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Atomoxetine. Approved Atracurium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Atracurium. Approved, Experimental, Investigational Atracurium besylate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Atracurium besylate. Approved Atropine The risk or severity of adverse effects can be increased when Atropine is combined with Diphenhydramine. Approved, Vet Approved Azaperone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Azaperone. Investigational, Vet Approved Azatadine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Azatadine. Approved AZD-3043 The risk or severity of adverse effects can be increased when Diphenhydramine is combined with AZD-3043. Investigational Azelastine Diphenhydramine may increase the central nervous system depressant (CNS depressant) activities of Azelastine. Approved Azithromycin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Azithromycin. Approved Baclofen The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Baclofen. Approved Barbexaclone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Barbexaclone. Experimental Barbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Barbital. Illicit Barbituric acid derivative The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Barbituric acid derivative. Experimental, Illicit Beclamide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Beclamide. Experimental Bedaquiline The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Bedaquiline. Approved Befunolol The metabolism of Befunolol can be decreased when combined with Diphenhydramine. Experimental Bekanamycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Bekanamycin. Experimental Benactyzine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Benactyzine. Withdrawn Bendroflumethiazide The serum concentration of Bendroflumethiazide can be increased when it is combined with Diphenhydramine. Approved Benmoxin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Benmoxin. Withdrawn Benperidol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Benperidol. Approved, Investigational Benzatropine The risk or severity of adverse effects can be increased when Benzatropine is combined with Diphenhydramine. Approved Benzilone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Benzilone. Experimental Benzoctamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Benzoctamine. Approved Benzphetamine The risk or severity of serotonin syndrome can be increased when Diphenhydramine is combined with Benzphetamine. Approved, Illicit Benzquinamide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Benzquinamide. Withdrawn Benzthiazide The serum concentration of Benzthiazide can be increased when it is combined with Diphenhydramine. Approved Benzyl alcohol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Benzyl alcohol. Approved Benzylpenicilloyl Polylysine Diphenhydramine may decrease effectiveness of Benzylpenicilloyl Polylysine as a diagnostic agent. Approved Bepridil The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Bepridil. Approved, Withdrawn Besifloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Besifloxacin. Approved Betahistine The therapeutic efficacy of Betahistine can be decreased when used in combination with Diphenhydramine. Approved, Investigational Betaxolol The metabolism of Betaxolol can be decreased when combined with Diphenhydramine. Approved, Investigational Bevantolol The metabolism of Bevantolol can be decreased when combined with Diphenhydramine. Approved Bevonium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Bevonium. Experimental Bezitramide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Bezitramide. Experimental, Illicit, Withdrawn Bifemelane The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Bifemelane. Experimental Bifeprunox The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Bifeprunox. Investigational Bilastine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Bilastine. Approved, Investigational Biperiden The risk or severity of adverse effects can be increased when Biperiden is combined with Diphenhydramine. Approved, Investigational Bisacodyl The therapeutic efficacy of Bisacodyl can be decreased when used in combination with Diphenhydramine. Approved Bisoprolol The metabolism of Bisoprolol can be decreased when combined with Diphenhydramine. Approved Bisoxatin The therapeutic efficacy of Bisoxatin can be decreased when used in combination with Diphenhydramine. Approved BL-1020 The risk or severity of adverse effects can be increased when Diphenhydramine is combined with BL-1020. Investigational Blonanserin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Blonanserin. Approved, Investigational Bopindolol The metabolism of Bopindolol can be decreased when combined with Diphenhydramine. Approved Bornaprine The risk or severity of adverse effects can be increased when Bornaprine is combined with Diphenhydramine. Experimental Bortezomib The risk or severity of QTc prolongation can be increased when Bortezomib is combined with Diphenhydramine. Approved, Investigational Botulinum Toxin Type A The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Botulinum Toxin Type A. Approved, Investigational Botulinum Toxin Type B The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Botulinum Toxin Type B. Approved, Investigational Brexpiprazole The serum concentration of Brexpiprazole can be increased when it is combined with Diphenhydramine. Approved, Investigational Brimonidine Brimonidine may increase the central nervous system depressant (CNS depressant) activities of Diphenhydramine. Approved Brivaracetam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Brivaracetam. Approved, Investigational Brofaromine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Brofaromine. Experimental Bromazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Bromazepam. Approved, Illicit, Investigational Bromisoval The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Bromisoval. Experimental Bromperidol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Bromperidol. Approved, Investigational Brompheniramine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Brompheniramine. Approved Brotizolam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Brotizolam. Approved, Investigational, Withdrawn Bucindolol The metabolism of Bucindolol can be decreased when combined with Diphenhydramine. Investigational Buclizine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Buclizine. Approved Bufotenine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Bufotenine. Experimental, Illicit Bufuralol The metabolism of Bufuralol can be decreased when combined with Diphenhydramine. Experimental, Investigational Bupranolol The metabolism of Bupranolol can be decreased when combined with Diphenhydramine. Approved Buprenorphine Diphenhydramine may increase the central nervous system depressant (CNS depressant) activities of Buprenorphine. Approved, Illicit, Investigational, Vet Approved Bupropion The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Bupropion. Approved Buserelin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Buserelin. Approved, Investigational Buspirone The risk or severity of adverse effects can be increased when Buspirone is combined with Diphenhydramine. Approved, Investigational Butabarbital The risk or severity of adverse effects can be increased when Butabarbital is combined with Diphenhydramine. Approved, Illicit Butalbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Butalbital. Approved, Illicit Butaperazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Butaperazine. Experimental Butethal The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Butethal. Approved, Illicit Butorphanol The risk or severity of adverse effects can be increased when Butorphanol is combined with Diphenhydramine. Approved, Illicit, Vet Approved Butriptyline The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Butriptyline. Approved Butylscopolamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Butylscopolamine. Approved, Investigational, Vet Approved Camazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Camazepam. Approved, Illicit Camylofin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Camylofin. Experimental Cannabidiol The risk or severity of Tachycardia and drowsiness can be increased when Diphenhydramine is combined with Cannabidiol. Approved, Investigational Cannabidivarin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cannabidivarin. Investigational Capreomycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Capreomycin. Approved Captodiame The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Captodiame. Approved, Investigational Carbamazepine The risk or severity of adverse effects can be increased when Carbamazepine is combined with Diphenhydramine. Approved, Investigational Carbinoxamine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Carbinoxamine. Approved Carboxymethylcellulose The therapeutic efficacy of Carboxymethylcellulose can be decreased when used in combination with Diphenhydramine. Approved, Investigational Carbromal The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Carbromal. Experimental Carfentanil The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Carfentanil. Illicit, Investigational, Vet Approved Cariprazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cariprazine. Approved, Investigational Carisbamate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Carisbamate. Investigational Carisoprodol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Carisoprodol. Approved Caroxazone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Caroxazone. Withdrawn Carteolol The metabolism of Carteolol can be decreased when combined with Diphenhydramine. Approved Carvedilol The metabolism of Carvedilol can be decreased when combined with Diphenhydramine. Approved, Investigational Castor oil The therapeutic efficacy of Castor oil can be decreased when used in combination with Diphenhydramine. Approved, Investigational, Nutraceutical, Vet Approved Cathinone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cathinone. Illicit Celiprolol The metabolism of Celiprolol can be decreased when combined with Diphenhydramine. Approved, Investigational Ceritinib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Ceritinib. Approved Cetirizine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cetirizine. Approved Chloral hydrate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Chloral hydrate. Approved, Illicit, Investigational, Vet Approved Chlorcyclizine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Chlorcyclizine. Approved Chlordiazepoxide The risk or severity of adverse effects can be increased when Chlordiazepoxide is combined with Diphenhydramine. Approved, Illicit, Investigational Chlormezanone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Chlormezanone. Approved, Investigational, Withdrawn Chloroprocaine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Chloroprocaine. Approved Chloroquine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Chloroquine. Approved, Investigational, Vet Approved Chlorothiazide The serum concentration of Chlorothiazide can be increased when it is combined with Diphenhydramine. Approved, Vet Approved Chlorphenamine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Chlorphenamine. Approved Chlorphenesin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Chlorphenesin. Approved, Vet Approved, Withdrawn Chlorphenoxamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Chlorphenoxamine. Withdrawn Chlorphentermine Chlorphentermine may decrease the sedative and stimulatory activities of Diphenhydramine. Illicit, Withdrawn Chlorproethazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Chlorproethazine. Experimental Chlorpromazine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Chlorpromazine. Approved, Investigational, Vet Approved Chlorprothixene The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Chlorprothixene. Approved, Investigational, Withdrawn Chlortetracycline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Chlortetracycline. Approved, Investigational, Vet Approved Chlorthalidone The serum concentration of Chlorthalidone can be increased when it is combined with Diphenhydramine. Approved Chlorzoxazone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Chlorzoxazone. Approved Choline The serum concentration of Choline can be increased when it is combined with Diphenhydramine. Approved, Nutraceutical Choline salicylate The serum concentration of Choline salicylate can be increased when it is combined with Diphenhydramine. Approved, Nutraceutical Cilostazol The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Cilostazol. Approved, Investigational Cimetidine The serum concentration of Cimetidine can be increased when it is combined with Diphenhydramine. Approved, Investigational Cimetropium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cimetropium. Experimental, Investigational Cinnarizine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Cinnarizine. Approved, Investigational Cinolazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cinolazepam. Approved Cinoxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Cinoxacin. Approved, Investigational, Withdrawn Ciprofloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Ciprofloxacin. Approved, Investigational Cisapride The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Cisapride. Approved, Investigational, Withdrawn Cisatracurium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cisatracurium. Approved Cisplatin The serum concentration of Cisplatin can be increased when it is combined with Diphenhydramine. Approved Citalopram The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Citalopram. Approved Clarithromycin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Clarithromycin. Approved Clemastine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Clemastine. Approved, Investigational Clidinium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Clidinium. Approved Clindamycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Clindamycin. Approved, Vet Approved Clobazam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Clobazam. Approved, Illicit clomethiazole The risk or severity of adverse effects can be increased when Diphenhydramine is combined with clomethiazole. Investigational Clomipramine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Clomipramine. Approved, Investigational, Vet Approved Clomocycline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Clomocycline. Approved Clonazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Clonazepam. Approved, Illicit Clonidine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Clonidine. Approved Clopenthixol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Clopenthixol. Experimental Cloranolol The metabolism of Cloranolol can be decreased when combined with Diphenhydramine. Experimental Clorazepate The risk or severity of adverse effects can be increased when Clorazepate is combined with Diphenhydramine. Approved, Illicit Clothiapine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Clothiapine. Experimental Clotiazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Clotiazepam. Approved, Illicit Cloxazolam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cloxazolam. Approved, Investigational Clozapine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Clozapine. Approved Cocaine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Cocaine. Approved, Illicit Codeine The therapeutic efficacy of Codeine can be decreased when used in combination with Diphenhydramine. Approved, Illicit Colistimethate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Colistimethate. Approved, Vet Approved Colistin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Colistin. Approved Coumaphos The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Coumaphos. Vet Approved CP-945598 The risk or severity of Tachycardia and drowsiness can be increased when Diphenhydramine is combined with CP-945598. Investigational Crizotinib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Crizotinib. Approved CUDC-101 The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with CUDC-101. Investigational CUDC-907 The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with CUDC-907. Investigational Cyamemazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cyamemazine. Approved Cyclizine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cyclizine. Approved Cyclobarbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cyclobarbital. Experimental Cyclobenzaprine The risk or severity of adverse effects can be increased when Cyclobenzaprine is combined with Diphenhydramine. Approved Cyclopenthiazide The serum concentration of Cyclopenthiazide can be increased when it is combined with Diphenhydramine. Experimental Cyclopentolate The risk or severity of adverse effects can be increased when Cyclopentolate is combined with Diphenhydramine. Approved Cyclopropane The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cyclopropane. Experimental Cyclosporine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cyclosporine. Approved, Investigational, Vet Approved Cycrimine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cycrimine. Approved Cyproheptadine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Cyproheptadine. Approved Dabrafenib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Dabrafenib. Approved, Investigational Danthron The therapeutic efficacy of Danthron can be decreased when used in combination with Diphenhydramine. Approved, Investigational, Withdrawn Dantrolene The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dantrolene. Approved, Investigational Dapiprazole The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dapiprazole. Approved Dapoxetine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dapoxetine. Investigational Darifenacin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Darifenacin. Approved, Investigational Dasatinib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Dasatinib. Approved, Investigational Deanol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Deanol. Experimental Decamethonium The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Decamethonium. Approved Degarelix The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Degarelix. Approved Delamanid The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Delamanid. Approved, Investigational Delorazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Delorazepam. Approved, Illicit, Investigational Demecarium The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Demecarium. Approved Demeclocycline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Demeclocycline. Approved Deramciclane The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Deramciclane. Investigational Desflurane The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Desflurane. Approved Desipramine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Desipramine. Approved, Investigational Desloratadine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Desloratadine. Approved, Investigational Desvenlafaxine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Desvenlafaxine. Approved, Investigational Detomidine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Detomidine. Vet Approved Dexbrompheniramine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dexbrompheniramine. Approved Dexchlorpheniramine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Dexchlorpheniramine. Experimental, Investigational Dexchlorpheniramine maleate The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Dexchlorpheniramine maleate. Approved Dexetimide The risk or severity of adverse effects can be increased when Dexetimide is combined with Diphenhydramine. Withdrawn Dexmedetomidine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dexmedetomidine. Approved, Vet Approved Dextofisopam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dextofisopam. Investigational Dextroamphetamine Dextroamphetamine may decrease the sedative and stimulatory activities of Diphenhydramine. Approved, Illicit Dextromethorphan The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dextromethorphan. Approved Dextromoramide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dextromoramide. Experimental, Illicit Dextropropoxyphene The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dextropropoxyphene. Approved, Illicit, Investigational, Withdrawn Dezocine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dezocine. Approved, Investigational Diazepam The risk or severity of adverse effects can be increased when Diazepam is combined with Diphenhydramine. Approved, Illicit, Investigational, Vet Approved Dibekacin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dibekacin. Experimental Dibenzepin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dibenzepin. Experimental Dichloralphenazone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dichloralphenazone. Approved, Illicit Dichlorvos The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Dichlorvos. Vet Approved Dicyclomine The risk or severity of adverse effects can be increased when Dicyclomine is combined with Diphenhydramine. Approved Diethyl ether The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Diethyl ether. Experimental Diethylpropion Diethylpropion may decrease the sedative and stimulatory activities of Diphenhydramine. Approved, Illicit Difemerine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Difemerine. Experimental Difenoxin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Difenoxin. Approved, Illicit Difloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Difloxacin. Vet Approved Dihexyverine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dihexyverine. Experimental Dihydrocodeine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dihydrocodeine. Approved, Illicit Dihydroetorphine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dihydroetorphine. Experimental, Illicit Dihydromorphine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dihydromorphine. Experimental, Illicit Dihydrostreptomycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dihydrostreptomycin. Investigational, Vet Approved Dimenhydrinate The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Dimenhydrinate. Approved Dimetacrine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dimetacrine. Approved, Withdrawn Dimethyltryptamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dimethyltryptamine. Experimental, Illicit Dimetindene The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dimetindene. Approved, Investigational Diphemanil The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Diphemanil. Experimental Diphemanil Methylsulfate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Diphemanil Methylsulfate. Approved, Vet Approved, Withdrawn Diphenidol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Diphenidol. Approved, Investigational, Withdrawn Diphenoxylate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Diphenoxylate. Approved, Illicit Disopyramide The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Disopyramide. Approved Distigmine The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Distigmine. Experimental Dixyrazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dixyrazine. Experimental Docusate The therapeutic efficacy of Docusate can be decreased when used in combination with Diphenhydramine. Approved Dofetilide The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Dofetilide. Approved, Investigational Dolasetron The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Dolasetron. Approved, Investigational Domoic Acid The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Domoic Acid. Experimental Domperidone The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Domperidone. Approved, Investigational, Vet Approved Donepezil The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Donepezil. Approved Dopamine The serum concentration of Dopamine can be increased when it is combined with Diphenhydramine. Approved Doramectin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Doramectin. Vet Approved Dosulepin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dosulepin. Approved Dotarizine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dotarizine. Investigational Doxacurium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Doxacurium. Approved Doxefazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Doxefazepam. Experimental Doxepin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Doxepin. Approved, Investigational Doxorubicin The serum concentration of Doxorubicin can be increased when it is combined with Diphenhydramine. Approved, Investigational Doxycycline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Doxycycline. Approved, Investigational, Vet Approved Doxylamine Doxylamine may increase the central nervous system depressant (CNS depressant) activities of Diphenhydramine. Approved, Vet Approved DPDPE The risk or severity of adverse effects can be increased when Diphenhydramine is combined with DPDPE. Experimental Dronabinol Dronabinol may increase the central nervous system depressant (CNS depressant) activities of Diphenhydramine. Approved, Illicit Dronedarone The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Dronedarone. Approved Droperidol Droperidol may increase the central nervous system depressant (CNS depressant) activities of Diphenhydramine. Approved, Vet Approved Drotebanol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Drotebanol. Experimental, Illicit Duloxetine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Duloxetine. Approved Dyclonine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Dyclonine. Approved Ebastine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Ebastine. Approved, Investigational Echothiophate The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Echothiophate. Approved Ecopipam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ecopipam. Investigational Edivoxetine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Edivoxetine. Investigational Edrophonium The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Edrophonium. Approved Efavirenz The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Efavirenz. Approved, Investigational Elagolix The metabolism of Elagolix can be decreased when combined with Diphenhydramine. Approved, Investigational Eliglustat The serum concentration of Eliglustat can be increased when it is combined with Diphenhydramine. Approved Eltanolone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Eltanolone. Investigational Eluxadoline The risk or severity of constipation can be increased when Diphenhydramine is combined with Eluxadoline. Approved, Investigational Emedastine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Emedastine. Approved Emepronium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Emepronium. Experimental Emylcamate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Emylcamate. Experimental Enflurane The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Enflurane. Approved, Investigational, Vet Approved Enoxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Enoxacin. Approved, Investigational Entacapone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Entacapone. Approved, Investigational Entinostat The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Entinostat. Investigational Epanolol The metabolism of Epanolol can be decreased when combined with Diphenhydramine. Experimental Eperisone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Eperisone. Approved, Investigational Epinastine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Epinastine. Approved, Investigational Epinephrine The serum concentration of Epinephrine can be increased when it is combined with Diphenhydramine. Approved, Vet Approved Epitizide The serum concentration of Epitizide can be increased when it is combined with Diphenhydramine. Experimental Eribulin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Eribulin. Approved, Investigational Erlotinib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Erlotinib. Approved, Investigational Erythromycin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Erythromycin. Approved, Investigational, Vet Approved Esatenolol The metabolism of Esatenolol can be decreased when combined with Diphenhydramine. Experimental Escitalopram The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Escitalopram. Approved, Investigational Eslicarbazepine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Eslicarbazepine. Approved Eslicarbazepine acetate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Eslicarbazepine acetate. Approved Esmirtazapine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Esmirtazapine. Investigational Esmolol The metabolism of Esmolol can be decreased when combined with Diphenhydramine. Approved Esreboxetine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Esreboxetine. Investigational Estazolam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Estazolam. Approved, Illicit Eszopiclone The risk or severity of adverse effects can be increased when Eszopiclone is combined with Diphenhydramine. Approved, Investigational Etacrynic acid The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Etacrynic acid. Approved, Investigational Etanautine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Etanautine. Experimental Ethadione The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ethadione. Experimental Ethanol Diphenhydramine may increase the central nervous system depressant (CNS depressant) activities of Ethanol. Approved Ethchlorvynol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ethchlorvynol. Approved, Illicit, Withdrawn Ethopropazine The risk or severity of adverse effects can be increased when Ethopropazine is combined with Diphenhydramine. Approved Ethosuximide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ethosuximide. Approved Ethotoin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ethotoin. Approved Ethyl carbamate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ethyl carbamate. Withdrawn Ethyl chloride The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ethyl chloride. Approved, Experimental, Investigational Ethyl loflazepate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ethyl loflazepate. Approved, Illicit Ethylmorphine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ethylmorphine. Approved, Illicit Etifoxine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Etifoxine. Investigational, Withdrawn Etiracetam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Etiracetam. Investigational Etizolam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Etizolam. Approved Etomidate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Etomidate. Approved Etoperidone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Etoperidone. Withdrawn Etorphine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Etorphine. Illicit, Vet Approved Etybenzatropine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Etybenzatropine. Experimental Ezogabine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ezogabine. Approved, Investigational Fabomotizole The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fabomotizole. Experimental Famotidine The risk or severity of QTc prolongation can be increased when Famotidine is combined with Diphenhydramine. Approved Fazadinium bromide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fazadinium bromide. Experimental Febarbamate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Febarbamate. Experimental Felbamate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Felbamate. Approved Fencamfamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fencamfamine. Approved, Illicit, Withdrawn Fenpiverinium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fenpiverinium. Experimental Fentanyl The risk or severity of serotonin syndrome can be increased when Fentanyl is combined with Diphenhydramine. Approved, Illicit, Investigational, Vet Approved Fenthion The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Fenthion. Vet Approved Fenyramidol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fenyramidol. Experimental Fesoterodine The serum concentration of the active metabolites of Fesoterodine can be increased when Fesoterodine is used in combination with Diphenhydramine. Approved Fexofenadine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Fexofenadine. Approved, Investigational Fingolimod The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Fingolimod. Approved, Investigational Flavoxate The risk or severity of adverse effects can be increased when Flavoxate is combined with Diphenhydramine. Approved Flecainide The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Flecainide. Approved, Withdrawn Fleroxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Fleroxacin. Approved Flibanserin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Flibanserin. Approved, Investigational Fluanisone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fluanisone. Experimental Fluconazole The risk or severity of QTc prolongation can be increased when Fluconazole is combined with Diphenhydramine. Approved, Investigational Fludiazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fludiazepam. Approved, Illicit Flumequine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Flumequine. Withdrawn Flunarizine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Flunarizine. Approved Flunitrazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Flunitrazepam. Approved, Illicit Fluoxetine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Fluoxetine. Approved, Vet Approved Flupentixol The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Flupentixol. Approved, Investigational, Withdrawn Fluphenazine The risk or severity of adverse effects can be increased when Fluphenazine is combined with Diphenhydramine. Approved Flurazepam The risk or severity of adverse effects can be increased when Flurazepam is combined with Diphenhydramine. Approved, Illicit, Investigational Fluspirilene The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fluspirilene. Approved, Investigational Fluticasone propionate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fluticasone propionate. Approved Fluvoxamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fluvoxamine. Approved, Investigational Formoterol The risk or severity of QTc prolongation can be increased when Formoterol is combined with Diphenhydramine. Approved, Investigational Foscarnet The risk or severity of QTc prolongation can be increased when Foscarnet is combined with Diphenhydramine. Approved Fosphenytoin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fosphenytoin. Approved, Investigational Fospropofol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fospropofol. Approved, Illicit, Investigational Framycetin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Framycetin. Approved Furazolidone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Furazolidone. Approved, Investigational, Vet Approved Gabapentin The risk or severity of adverse effects can be increased when Gabapentin is combined with Diphenhydramine. Approved, Investigational Gabapentin Enacarbil The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Gabapentin Enacarbil. Approved, Investigational Gaboxadol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Gaboxadol. Investigational Gadobenic acid The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Gadobenic acid. Approved, Investigational Galantamine The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Galantamine. Approved Gallamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Gallamine. Experimental Gallamine Triethiodide The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Gallamine Triethiodide. Approved Gamma Hydroxybutyric Acid The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Gamma Hydroxybutyric Acid. Approved, Illicit, Investigational Gantacurium Chloride The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Gantacurium Chloride. Investigational Garenoxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Garenoxacin. Investigational Gatifloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Gatifloxacin. Approved, Investigational Gedocarnil The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Gedocarnil. Experimental Gemifloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Gemifloxacin. Approved, Investigational Geneticin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Geneticin. Experimental Gentamicin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Gentamicin. Approved, Vet Approved GENTAMICIN C1A The risk or severity of adverse effects can be increased when Diphenhydramine is combined with GENTAMICIN C1A. Experimental Gepefrine Gepefrine may decrease the sedative and stimulatory activities of Diphenhydramine. Experimental Gepirone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Gepirone. Investigational Ginkgo biloba The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Ginkgo biloba. Approved, Investigational, Nutraceutical Givinostat The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Givinostat. Investigational Glucagon recombinant Diphenhydramine may increase the gastrointestinal motility reducing activities of Glucagon recombinant. Approved Glutethimide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Glutethimide. Approved, Illicit Glycerin The therapeutic efficacy of Glycerin can be decreased when used in combination with Diphenhydramine. Approved, Investigational Glycopyrronium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Glycopyrronium. Approved, Investigational, Vet Approved Goserelin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Goserelin. Approved Granisetron The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Granisetron. Approved, Investigational Grepafloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Grepafloxacin. Approved, Investigational, Withdrawn Guanfacine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Guanfacine. Approved, Investigational GW842166 The risk or severity of Tachycardia and drowsiness can be increased when Diphenhydramine is combined with GW842166. Investigational Halazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Halazepam. Approved, Illicit, Withdrawn Halofantrine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Halofantrine. Approved Haloperidol The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Haloperidol. Approved Halothane The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Halothane. Approved, Vet Approved Harmaline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Harmaline. Experimental Heptabarbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Heptabarbital. Approved Heroin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Heroin. Approved, Illicit, Investigational Hexafluronium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Hexafluronium. Approved Hexamethonium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Hexamethonium. Experimental Hexapropymate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Hexapropymate. Experimental Hexobarbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Hexobarbital. Approved Hexocyclium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Hexocyclium. Approved Histamine The serum concentration of Histamine can be increased when it is combined with Diphenhydramine. Approved, Investigational Histrelin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Histrelin. Approved Homatropine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Homatropine. Approved Homatropine Methylbromide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Homatropine Methylbromide. Approved Huperzine A The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Huperzine A. Approved, Investigational Hyaluronidase The therapeutic efficacy of Hyaluronidase can be decreased when used in combination with Diphenhydramine. Approved, Investigational Hydracarbazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Hydracarbazine. Experimental Hydrochlorothiazide The serum concentration of Hydrochlorothiazide can be increased when it is combined with Diphenhydramine. Approved, Vet Approved Hydrocodone Diphenhydramine may increase the central nervous system depressant (CNS depressant) activities of Hydrocodone. Approved, Illicit Hydroflumethiazide The serum concentration of Hydroflumethiazide can be increased when it is combined with Diphenhydramine. Approved, Investigational Hydromorphone The risk or severity of adverse effects can be increased when Hydromorphone is combined with Diphenhydramine. Approved, Illicit Hydroxyamphetamine Hydroxyamphetamine may decrease the sedative and stimulatory activities of Diphenhydramine. Approved Hydroxychloroquine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Hydroxychloroquine. Approved Hydroxyzine Hydroxyzine may increase the central nervous system depressant (CNS depressant) activities of Diphenhydramine. Approved Hygromycin B The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Hygromycin B. Vet Approved Hyoscyamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Hyoscyamine. Approved Hypericin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Hypericin. Investigational Ibandronate The risk or severity of QTc prolongation can be increased when Ibandronate is combined with Diphenhydramine. Approved, Investigational Ibipinabant The risk or severity of Tachycardia and drowsiness can be increased when Diphenhydramine is combined with Ibipinabant. Investigational Ibutilide The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Ibutilide. Approved Ifenprodil The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ifenprodil. Approved, Investigational, Withdrawn Iloperidone The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Iloperidone. Approved Imagabalin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Imagabalin. Investigational Imatinib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Imatinib. Approved Imidafenacin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Imidafenacin. Approved, Investigational Imipramine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Imipramine. Approved Imipramine oxide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Imipramine oxide. Experimental Indacaterol The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Indacaterol. Approved Indalpine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Indalpine. Investigational, Withdrawn Indapamide The serum concentration of Indapamide can be increased when it is combined with Diphenhydramine. Approved Indenolol The metabolism of Indenolol can be decreased when combined with Diphenhydramine. Withdrawn Indiplon The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Indiplon. Investigational Iofetamine I-123 Iofetamine I-123 may decrease the sedative and stimulatory activities of Diphenhydramine. Approved Ipidacrine The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Ipidacrine. Experimental Ipratropium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ipratropium. Approved Iprindole The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Iprindole. Experimental Iproclozide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Iproclozide. Withdrawn Iproniazid The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Iproniazid. Withdrawn Isepamicin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Isepamicin. Experimental Isocarboxazid The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Isocarboxazid. Approved Isoflurane The risk or severity of adverse effects can be increased when Isoflurane is combined with Diphenhydramine. Approved, Vet Approved Isoflurophate The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Isoflurophate. Approved, Investigational, Withdrawn Isopropamide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Isopropamide. Approved, Vet Approved Isradipine The risk or severity of QTc prolongation can be increased when Isradipine is combined with Diphenhydramine. Approved, Investigational Itopride The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Itopride. Investigational Itraconazole The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Itraconazole. Approved, Investigational Ivabradine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Ivabradine. Approved Ivosidenib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Ivosidenib. Approved, Investigational Kanamycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Kanamycin. Approved, Investigational, Vet Approved Ketamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ketamine. Approved, Vet Approved Ketazolam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ketazolam. Approved Ketobemidone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ketobemidone. Approved, Investigational Ketoconazole The risk or severity of QTc prolongation can be increased when Ketoconazole is combined with Diphenhydramine. Approved, Investigational Ketotifen The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Ketotifen. Approved L-Tryptophan The risk or severity of adverse effects can be increased when Diphenhydramine is combined with L-Tryptophan. Approved, Nutraceutical, Withdrawn Labetalol The metabolism of Labetalol can be decreased when combined with Diphenhydramine. Approved Lacosamide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lacosamide. Approved Lactitol The therapeutic efficacy of Lactitol can be decreased when used in combination with Diphenhydramine. Investigational Lactulose The therapeutic efficacy of Lactulose can be decreased when used in combination with Diphenhydramine. Approved Lamivudine The serum concentration of Lamivudine can be increased when it is combined with Diphenhydramine. Approved, Investigational Lamotrigine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lamotrigine. Approved, Investigational Landiolol The metabolism of Landiolol can be decreased when combined with Diphenhydramine. Investigational Lanicemine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lanicemine. Investigational Lapatinib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Lapatinib. Approved, Investigational Lenvatinib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Lenvatinib. Approved, Investigational Leuprolide The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Leuprolide. Approved, Investigational Levetiracetam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Levetiracetam. Approved, Investigational Levobetaxolol The metabolism of Levobetaxolol can be decreased when combined with Diphenhydramine. Approved, Investigational Levobunolol The metabolism of Levobunolol can be decreased when combined with Diphenhydramine. Approved Levocabastine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Levocabastine. Approved, Investigational Levocetirizine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Levocetirizine. Approved Levodopa The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Levodopa. Approved Levofloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Levofloxacin. Approved, Investigational Levomethadyl Acetate The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Levomethadyl Acetate. Approved, Investigational Levomilnacipran The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Levomilnacipran. Approved, Investigational Levorphanol The risk or severity of adverse effects can be increased when Levorphanol is combined with Diphenhydramine. Approved Linaclotide The therapeutic efficacy of Linaclotide can be decreased when used in combination with Diphenhydramine. Approved Lincomycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lincomycin. Approved, Vet Approved Linezolid The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Linezolid. Approved, Investigational Lisdexamfetamine Lisdexamfetamine may decrease the sedative and stimulatory activities of Diphenhydramine. Approved, Investigational Lithium carbonate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lithium carbonate. Approved Lithium cation The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Lithium cation. Experimental Lofentanil The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lofentanil. Illicit Lofepramine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lofepramine. Experimental Lofexidine The therapeutic efficacy of Diphenhydramine can be increased when used in combination with Lofexidine. Approved, Investigational Lomefloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Lomefloxacin. Approved, Investigational Lopinavir The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Lopinavir. Approved Loprazolam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Loprazolam. Experimental Loratadine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Loratadine. Approved, Investigational Lorazepam The risk or severity of adverse effects can be increased when Lorazepam is combined with Diphenhydramine. Approved Lormetazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lormetazepam. Approved Lortalamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lortalamine. Experimental Loxapine The risk or severity of adverse effects can be increased when Loxapine is combined with Diphenhydramine. Approved Lubiprostone The therapeutic efficacy of Lubiprostone can be decreased when used in combination with Diphenhydramine. Approved, Investigational Lumateperone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lumateperone. Investigational Lumefantrine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Lumefantrine. Approved Lurasidone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lurasidone. Approved, Investigational Lymecycline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lymecycline. Approved, Investigational Lysergic Acid Diethylamide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Lysergic Acid Diethylamide. Illicit, Investigational, Withdrawn Macimorelin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Macimorelin. Approved, Investigational Magnesium acetate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium acetate. Approved Magnesium acetate tetrahydrate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium acetate tetrahydrate. Approved Magnesium Aluminum Silicate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium Aluminum Silicate. Approved Magnesium aspartate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium aspartate. Experimental Magnesium carbonate The therapeutic efficacy of Magnesium carbonate can be decreased when used in combination with Diphenhydramine. Approved, Investigational Magnesium cation The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium cation. Approved, Nutraceutical Magnesium chloride The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium chloride. Approved Magnesium citrate The therapeutic efficacy of Magnesium citrate can be decreased when used in combination with Diphenhydramine. Approved Magnesium gluconate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium gluconate. Approved, Investigational Magnesium glycinate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium glycinate. Approved Magnesium hydroxide The therapeutic efficacy of Magnesium hydroxide can be decreased when used in combination with Diphenhydramine. Approved, Investigational Magnesium orotate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium orotate. Experimental Magnesium oxide The therapeutic efficacy of Magnesium oxide can be decreased when used in combination with Diphenhydramine. Approved Magnesium peroxide The therapeutic efficacy of Magnesium peroxide can be decreased when used in combination with Diphenhydramine. Experimental Magnesium phosphate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium phosphate. Experimental Magnesium silicate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium silicate. Approved Magnesium stearate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium stearate. Investigational Magnesium sulfate The therapeutic efficacy of Diphenhydramine can be increased when used in combination with Magnesium sulfate. Approved, Investigational, Vet Approved Magnesium Trisilicate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Magnesium Trisilicate. Approved Malathion The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Malathion. Approved, Investigational Mannitol The therapeutic efficacy of Mannitol can be decreased when used in combination with Diphenhydramine. Approved, Investigational Maprotiline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Maprotiline. Approved, Investigational Mazaticol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mazaticol. Experimental Mazindol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mazindol. Approved, Investigational Mebanazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mebanazine. Withdrawn Mebeverine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mebeverine. Approved, Investigational Mebicar The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mebicar. Experimental Mebutamate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mebutamate. Approved Mecamylamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mecamylamine. Approved, Investigational Meclizine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Meclizine. Approved Medazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Medazepam. Experimental Medetomidine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Medetomidine. Vet Approved Medifoxamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Medifoxamine. Experimental Mefloquine The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Mefloquine. Approved, Investigational Melatonin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Melatonin. Approved, Nutraceutical, Vet Approved Melitracen The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Melitracen. Experimental, Investigational Melperone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Melperone. Approved, Investigational Memantine The serum concentration of Memantine can be increased when it is combined with Diphenhydramine. Approved, Investigational Mepenzolate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mepenzolate. Approved Mephedrone Mephedrone may decrease the sedative and stimulatory activities of Diphenhydramine. Investigational Mephenesin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mephenesin. Approved Mephenoxalone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mephenoxalone. Experimental Mephentermine Mephentermine may decrease the sedative and stimulatory activities of Diphenhydramine. Approved Mephenytoin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mephenytoin. Investigational, Withdrawn Mepindolol The metabolism of Mepindolol can be decreased when combined with Diphenhydramine. Experimental Meprobamate The risk or severity of adverse effects can be increased when Meprobamate is combined with Diphenhydramine. Approved, Illicit Meptazinol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Meptazinol. Experimental Mepyramine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Mepyramine. Approved, Vet Approved Mequitazine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Mequitazine. Approved Mesoridazine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Mesoridazine. Approved, Investigational Metaxalone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Metaxalone. Approved Metformin The serum concentration of Metformin can be increased when it is combined with Diphenhydramine. Approved Methacycline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methacycline. Approved, Investigational Methadone The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Methadone. Approved Methadyl Acetate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methadyl Acetate. Approved, Illicit Methamphetamine Methamphetamine may decrease the sedative and stimulatory activities of Diphenhydramine. Approved, Illicit Methanesulfonyl Fluoride The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Methanesulfonyl Fluoride. Investigational Methantheline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methantheline. Approved, Investigational Methapyrilene The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methapyrilene. Withdrawn Methaqualone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methaqualone. Illicit, Withdrawn Metharbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Metharbital. Withdrawn Methocarbamol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methocarbamol. Approved, Vet Approved Methohexital The risk or severity of adverse effects can be increased when Methohexital is combined with Diphenhydramine. Approved Methotrimeprazine Diphenhydramine may increase the central nervous system depressant (CNS depressant) activities of Methotrimeprazine. Approved, Investigational Methoxyflurane The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methoxyflurane. Approved, Investigational, Vet Approved Methoxyphenamine Methoxyphenamine may decrease the sedative and stimulatory activities of Diphenhydramine. Experimental Methscopolamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methscopolamine. Approved Methsuximide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methsuximide. Approved Methyclothiazide The serum concentration of Methyclothiazide can be increased when it is combined with Diphenhydramine. Approved Methyl cellulose The therapeutic efficacy of Methyl cellulose can be decreased when used in combination with Diphenhydramine. Approved Methylene blue The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methylene blue. Approved, Investigational Methylpentynol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methylpentynol. Experimental Methylphenobarbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methylphenobarbital. Approved Methylscopolamine bromide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methylscopolamine bromide. Approved Methyprylon The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Methyprylon. Approved, Illicit, Withdrawn Metipranolol The metabolism of Metipranolol can be decreased when combined with Diphenhydramine. Approved Metixene The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Metixene. Approved Metoclopramide The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Metoclopramide. Approved, Investigational Metocurine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Metocurine. Approved Metocurine Iodide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Metocurine Iodide. Approved, Withdrawn Metolazone The serum concentration of Metolazone can be increased when it is combined with Diphenhydramine. Approved Metoprolol The serum concentration of Metoprolol can be increased when it is combined with Diphenhydramine. Approved, Investigational Metronidazole The risk or severity of QTc prolongation can be increased when Metronidazole is combined with Diphenhydramine. Approved Metyrosine Diphenhydramine may increase the sedative activities of Metyrosine. Approved Mexiletine The metabolism of Mexiletine can be decreased when combined with Diphenhydramine. Approved, Investigational Mianserin Mianserin may increase the anticholinergic activities of Diphenhydramine. Approved, Investigational Micronomicin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Micronomicin. Experimental Midazolam The risk or severity of adverse effects can be increased when Midazolam is combined with Diphenhydramine. Approved, Illicit Midomafetamine Midomafetamine may decrease the sedative and stimulatory activities of Diphenhydramine. Experimental, Illicit, Investigational Mifepristone The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Mifepristone. Approved, Investigational Milnacipran The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Milnacipran. Approved, Investigational Minaprine The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Minaprine. Approved Mineral oil The therapeutic efficacy of Mineral oil can be decreased when used in combination with Diphenhydramine. Approved, Vet Approved Minocycline Minocycline may increase the central nervous system depressant (CNS depressant) activities of Diphenhydramine. Approved, Investigational Mirabegron The risk or severity of urinary retention can be increased when Diphenhydramine is combined with Mirabegron. Approved Mirtazapine Diphenhydramine may increase the central nervous system depressant (CNS depressant) activities of Mirtazapine. Approved Mivacurium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mivacurium. Approved MMDA MMDA may decrease the sedative and stimulatory activities of Diphenhydramine. Experimental, Illicit Mocetinostat The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Mocetinostat. Investigational Moclobemide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Moclobemide. Approved, Investigational Moexipril The risk or severity of QTc prolongation can be increased when Moexipril is combined with Diphenhydramine. Approved Molindone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Molindone. Approved Moperone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Moperone. Experimental Moricizine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Moricizine. Approved, Investigational, Withdrawn Morphine The risk or severity of adverse effects can be increased when Morphine is combined with Diphenhydramine. Approved, Investigational Mosapramine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Mosapramine. Experimental Moxifloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Moxifloxacin. Approved, Investigational MRK-409 The risk or severity of adverse effects can be increased when Diphenhydramine is combined with MRK-409. Experimental Nabilone Nabilone may increase the central nervous system depressant (CNS depressant) activities of Diphenhydramine. Approved, Investigational Nabiximols The risk or severity of Tachycardia and drowsiness can be increased when Diphenhydramine is combined with Nabiximols. Approved, Investigational Nadolol The metabolism of Nadolol can be decreased when combined with Diphenhydramine. Approved Nafamostat The serum concentration of Nafamostat can be increased when it is combined with Diphenhydramine. Approved, Investigational Nalbuphine The risk or severity of adverse effects can be increased when Nalbuphine is combined with Diphenhydramine. Approved Nalidixic Acid The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Nalidixic Acid. Approved, Investigational Naltrexone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Naltrexone. Approved, Investigational, Vet Approved Neamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Neamine. Experimental Nebivolol The serum concentration of Nebivolol can be increased when it is combined with Diphenhydramine. Approved, Investigational Nefazodone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Nefazodone. Approved, Withdrawn Nefiracetam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Nefiracetam. Investigational Nelfinavir The risk or severity of QTc prolongation can be increased when Nelfinavir is combined with Diphenhydramine. Approved Nemonoxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Nemonoxacin. Investigational Neocitrullamon The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Neocitrullamon. Experimental Neomycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Neomycin. Approved, Vet Approved Neosaxitoxin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Neosaxitoxin. Investigational Neostigmine The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Neostigmine. Approved, Vet Approved Netilmicin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Netilmicin. Approved, Investigational Nialamide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Nialamide. Withdrawn Niaprazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Niaprazine. Experimental Nicardipine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Nicardipine. Approved, Investigational Nicomorphine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Nicomorphine. Experimental Nifedipine The metabolism of Nifedipine can be decreased when combined with Diphenhydramine. Approved Nilotinib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Nilotinib. Approved, Investigational Nisoxetine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Nisoxetine. Experimental Nitrazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Nitrazepam. Approved Nitrous oxide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Nitrous oxide. Approved, Vet Approved Nomifensine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Nomifensine. Withdrawn Nordazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Nordazepam. Approved Norepinephrine The serum concentration of Norepinephrine can be increased when it is combined with Diphenhydramine. Approved Norfloxacin The risk or severity of QTc prolongation can be increased when Norfloxacin is combined with Diphenhydramine. Approved Normethadone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Normethadone. Approved, Illicit Nortriptyline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Nortriptyline. Approved Octamoxin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Octamoxin. Withdrawn Octreotide The risk or severity of QTc prolongation can be increased when Octreotide is combined with Diphenhydramine. Approved, Investigational Ofloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Ofloxacin. Approved Olanzapine The risk or severity of adverse effects can be increased when Olanzapine is combined with Diphenhydramine. Approved, Investigational Olodaterol The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Olodaterol. Approved Olopatadine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Olopatadine. Approved Ondansetron The risk or severity of serotonin syndrome can be increased when Ondansetron is combined with Diphenhydramine. Approved Opipramol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Opipramol. Investigational Opium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Opium. Approved, Illicit Orbifloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Orbifloxacin. Vet Approved Orphenadrine Diphenhydramine may increase the central nervous system depressant (CNS depressant) activities of Orphenadrine. Approved Orvepitant The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Orvepitant. Investigational Osanetant The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Osanetant. Investigational Otilonium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Otilonium. Experimental, Investigational Oxaflozane The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxaflozane. Experimental Oxaliplatin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Oxaliplatin. Approved, Investigational Oxaprotiline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxaprotiline. Experimental Oxatomide The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Oxatomide. Investigational Oxazepam The risk or severity of adverse effects can be increased when Oxazepam is combined with Diphenhydramine. Approved Oxcarbazepine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxcarbazepine. Approved Oxiracetam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxiracetam. Experimental Oxitriptan The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxitriptan. Approved, Investigational, Nutraceutical Oxitropium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxitropium. Investigational Oxolinic acid The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Oxolinic acid. Experimental Oxprenolol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxprenolol. Approved Oxybutynin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxybutynin. Approved, Investigational Oxycodone The risk or severity of adverse effects can be increased when Oxycodone is combined with Diphenhydramine. Approved, Illicit, Investigational Oxymorphone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxymorphone. Approved, Investigational, Vet Approved Oxypertine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxypertine. Experimental Oxyphencyclimine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxyphencyclimine. Approved Oxyphenisatin The therapeutic efficacy of Oxyphenisatin can be decreased when used in combination with Diphenhydramine. Investigational, Withdrawn Oxyphenonium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxyphenonium. Approved Oxytetracycline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Oxytetracycline. Approved, Investigational, Vet Approved Oxytocin The risk or severity of QTc prolongation can be increased when Oxytocin is combined with Diphenhydramine. Approved, Vet Approved Paliperidone The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Paliperidone. Approved Palmidrol The risk or severity of Tachycardia and drowsiness can be increased when Diphenhydramine is combined with Palmidrol. Experimental, Nutraceutical Pancuronium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pancuronium. Approved Panobinostat The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Panobinostat. Approved, Investigational Papaverine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Papaverine. Approved, Investigational Paraldehyde Diphenhydramine may increase the central nervous system depressant (CNS depressant) activities of Paraldehyde. Approved, Investigational Paramethadione The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Paramethadione. Approved Paraoxon The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Paraoxon. Experimental Pargyline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pargyline. Approved Paromomycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Paromomycin. Approved, Investigational Paroxetine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Paroxetine. Approved, Investigational Pasireotide The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Pasireotide. Approved Pazopanib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Pazopanib. Approved Pazufloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Pazufloxacin. Investigational Pefloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Pefloxacin. Approved Penbutolol The metabolism of Penbutolol can be decreased when combined with Diphenhydramine. Approved, Investigational Penfluridol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Penfluridol. Experimental Penimepicycline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Penimepicycline. Experimental Pentaerithrityl The therapeutic efficacy of Pentaerithrityl can be decreased when used in combination with Diphenhydramine. Experimental Pentamidine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Pentamidine. Approved, Investigational Pentazocine The risk or severity of adverse effects can be increased when Pentazocine is combined with Diphenhydramine. Approved, Vet Approved Penthienate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Penthienate. Experimental Pentobarbital The risk or severity of adverse effects can be increased when Pentobarbital is combined with Diphenhydramine. Approved, Investigational, Vet Approved Pentolinium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pentolinium. Approved Perampanel Perampanel may increase the central nervous system depressant (CNS depressant) activities of Diphenhydramine. Approved Perazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Perazine. Approved, Investigational Perflutren The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Perflutren. Approved Perospirone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Perospirone. Approved Perphenazine The risk or severity of adverse effects can be increased when Perphenazine is combined with Diphenhydramine. Approved Pethidine The risk or severity of adverse effects can be increased when Pethidine is combined with Diphenhydramine. Approved Phenacemide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Phenacemide. Approved Phenazocine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Phenazocine. Experimental Phencyclidine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Phencyclidine. Illicit Phenelzine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Phenelzine. Approved Phenethylamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Phenethylamine. Experimental Pheneturide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pheneturide. Experimental Phenglutarimide The risk or severity of adverse effects can be increased when Phenglutarimide is combined with Diphenhydramine. Experimental Phenibut The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Phenibut. Experimental Pheniprazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pheniprazine. Withdrawn Pheniramine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Pheniramine. Approved Phenobarbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Phenobarbital. Approved, Investigational Phenolphthalein The therapeutic efficacy of Phenolphthalein can be decreased when used in combination with Diphenhydramine. Approved, Withdrawn Phenoperidine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Phenoperidine. Experimental Phenoxypropazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Phenoxypropazine. Withdrawn Phenprobamate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Phenprobamate. Experimental Phensuximide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Phensuximide. Approved Phentermine Phentermine may decrease the sedative and stimulatory activities of Diphenhydramine. Approved, Illicit Phenytoin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Phenytoin. Approved, Vet Approved Physostigmine The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Physostigmine. Approved, Investigational Picosulfuric acid The therapeutic efficacy of Picosulfuric acid can be decreased when used in combination with Diphenhydramine. Approved Pimavanserin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pimavanserin. Approved, Investigational Pimozide The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Pimozide. Approved Pinazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pinazepam. Experimental Pindolol The metabolism of Pindolol can be decreased when combined with Diphenhydramine. Approved, Investigational Pipamperone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pipamperone. Approved, Investigational Pipecuronium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pipecuronium. Approved Pipemidic acid The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Pipemidic acid. Experimental Pipenzolate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pipenzolate. Experimental Piperidolate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Piperidolate. Experimental Pipotiazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pipotiazine. Approved, Investigational Pirenzepine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pirenzepine. Approved Piritramide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Piritramide. Approved, Investigational Pirlimycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pirlimycin. Vet Approved Pirlindole The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pirlindole. Approved Piromidic acid The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Piromidic acid. Experimental Pitolisant The therapeutic efficacy of Pitolisant can be decreased when used in combination with Diphenhydramine. Approved, Investigational Pivagabine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pivagabine. Investigational Pivhydrazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pivhydrazine. Withdrawn Pizotifen The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pizotifen. Approved Plantago seed The therapeutic efficacy of Plantago seed can be decreased when used in combination with Diphenhydramine. Approved, Investigational Plazomicin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Plazomicin. Approved, Investigational Plecanatide The therapeutic efficacy of Plecanatide can be decreased when used in combination with Diphenhydramine. Approved, Investigational Poldine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Poldine. Experimental Polycarbophil The therapeutic efficacy of Polycarbophil can be decreased when used in combination with Diphenhydramine. Approved Polyethylene glycol The therapeutic efficacy of Polyethylene glycol can be decreased when used in combination with Diphenhydramine. Approved, Vet Approved Polymyxin B Sulfate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Polymyxin B Sulfate. Approved, Vet Approved Polythiazide The serum concentration of Polythiazide can be increased when it is combined with Diphenhydramine. Approved Pomalidomide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pomalidomide. Approved Posaconazole The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Posaconazole. Approved, Investigational, Vet Approved Potassium acetate The therapeutic efficacy of Potassium acetate can be decreased when used in combination with Diphenhydramine. Approved, Investigational Potassium Chloride The risk or severity of gastrointestinal ulceration can be increased when Diphenhydramine is combined with Potassium Chloride. Approved, Withdrawn Pracinostat The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Pracinostat. Investigational Practolol The metabolism of Practolol can be decreased when combined with Diphenhydramine. Approved Pramipexole Diphenhydramine may increase the sedative activities of Pramipexole. Approved, Investigational Pramlintide The risk or severity of reduced gastrointestinal motility can be increased when Pramlintide is combined with Diphenhydramine. Approved, Investigational Prazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Prazepam. Approved, Illicit Prazosin The serum concentration of Prazosin can be increased when it is combined with Diphenhydramine. Approved Pregabalin The therapeutic efficacy of Diphenhydramine can be increased when used in combination with Pregabalin. Approved, Illicit, Investigational Pridinol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pridinol. Experimental Prifinium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Prifinium. Experimental Primaquine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Primaquine. Approved Primidone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Primidone. Approved, Vet Approved Probucol The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Probucol. Approved, Investigational Procainamide The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Procainamide. Approved Procaine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Procaine. Approved, Investigational, Vet Approved Procarbazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Procarbazine. Approved, Investigational Prochlorperazine The risk or severity of adverse effects can be increased when Prochlorperazine is combined with Diphenhydramine. Approved, Vet Approved Procyclidine The risk or severity of adverse effects can be increased when Procyclidine is combined with Diphenhydramine. Approved Progabide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Progabide. Approved, Investigational Progesterone The metabolism of Progesterone can be decreased when combined with Diphenhydramine. Approved, Vet Approved Promazine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Promazine. Approved, Vet Approved Promethazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Promethazine. Approved, Investigational Propafenone The serum concentration of Diphenhydramine can be increased when it is combined with Propafenone. Approved Propanidid The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Propanidid. Experimental Propantheline The risk or severity of adverse effects can be increased when Propantheline is combined with Diphenhydramine. Approved Propericiazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Propericiazine. Approved, Investigational Propiomazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Propiomazine. Approved Propiopromazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Propiopromazine. Vet Approved Propiverine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Propiverine. Approved, Investigational Propofol The risk or severity of adverse effects can be increased when Propofol is combined with Diphenhydramine. Approved, Investigational, Vet Approved Propranolol The metabolism of Propranolol can be decreased when combined with Diphenhydramine. Approved, Investigational Prothipendyl The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Prothipendyl. Investigational Protriptyline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Protriptyline. Approved Proxibarbal The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Proxibarbal. Experimental Prucalopride The therapeutic efficacy of Prucalopride can be decreased when used in combination with Diphenhydramine. Approved Prulifloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Prulifloxacin. Investigational Pseudoephedrine Pseudoephedrine may decrease the sedative and stimulatory activities of Diphenhydramine. Approved Psilocybine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Psilocybine. Investigational Puromycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Puromycin. Experimental Pyrantel The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pyrantel. Approved, Vet Approved Pyridostigmine The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Pyridostigmine. Approved, Investigational Pyrithyldione The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Pyrithyldione. Experimental Quazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Quazepam. Approved, Illicit Quetiapine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Quetiapine. Approved Quinethazone The serum concentration of Quinethazone can be increased when it is combined with Diphenhydramine. Approved Quinidine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Quinidine. Approved, Investigational Quinine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Quinine. Approved Quinupramine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Quinupramine. Experimental Raclopride The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Raclopride. Investigational Ramelteon The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ramelteon. Approved, Investigational Ramosetron The risk or severity of constipation can be increased when Diphenhydramine is combined with Ramosetron. Approved, Investigational Ranitidine The serum concentration of Ranitidine can be increased when it is combined with Diphenhydramine. Approved Ranolazine The risk or severity of QTc prolongation can be increased when Ranolazine is combined with Diphenhydramine. Approved, Investigational Rapacuronium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Rapacuronium. Withdrawn Rasagiline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Rasagiline. Approved Reboxetine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Reboxetine. Approved, Investigational Remacemide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Remacemide. Investigational Remifentanil The risk or severity of adverse effects can be increased when Remifentanil is combined with Diphenhydramine. Approved Remoxipride The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Remoxipride. Approved, Withdrawn Reposal The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Reposal. Approved Reserpine The risk or severity of adverse effects can be increased when Reserpine is combined with Diphenhydramine. Approved, Investigational Revefenacin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Revefenacin. Investigational Ribociclib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Ribociclib. Approved, Investigational Ribostamycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ribostamycin. Approved, Investigational Ricolinostat The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Ricolinostat. Investigational Rilpivirine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Rilpivirine. Approved Riluzole The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Riluzole. Approved, Investigational Rimonabant The risk or severity of Tachycardia and drowsiness can be increased when Diphenhydramine is combined with Rimonabant. Approved, Investigational Risperidone The risk or severity of adverse effects can be increased when Risperidone is combined with Diphenhydramine. Approved, Investigational Ritanserin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ritanserin. Investigational Ritobegron Ritobegron may decrease the sedative and stimulatory activities of Diphenhydramine. Investigational Ritonavir The risk or severity of QTc prolongation can be increased when Ritonavir is combined with Diphenhydramine. Approved, Investigational Rivastigmine The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Rivastigmine. Approved, Investigational Rizatriptan The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Rizatriptan. Approved Rociverine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Rociverine. Experimental Rocuronium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Rocuronium. Approved Rolipram The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Rolipram. Investigational Rolitetracycline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Rolitetracycline. Approved Romidepsin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Romidepsin. Approved, Investigational Romifidine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Romifidine. Vet Approved Ropinirole Diphenhydramine may increase the sedative activities of Ropinirole. Approved, Investigational Rosoxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Rosoxacin. Approved, Investigational Rotigotine Diphenhydramine may increase the sedative activities of Rotigotine. Approved Roxithromycin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Roxithromycin. Approved, Investigational, Withdrawn RP-5063 The risk or severity of adverse effects can be increased when Diphenhydramine is combined with RP-5063. Investigational Rufinamide The risk or severity of adverse effects can be increased when Rufinamide is combined with Diphenhydramine. Approved Rufloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Rufloxacin. Experimental Rupatadine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Rupatadine. Approved Safinamide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Safinamide. Approved, Investigational Safrazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Safrazine. Withdrawn Salbutamol The risk or severity of QTc prolongation can be increased when Salbutamol is combined with Diphenhydramine. Approved, Vet Approved Salmeterol The risk or severity of QTc prolongation can be increased when Salmeterol is combined with Diphenhydramine. Approved Saquinavir The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Saquinavir. Approved, Investigational Sarafloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Sarafloxacin. Vet Approved, Withdrawn Saredutant The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Saredutant. Investigational Scopolamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Scopolamine. Approved, Investigational Secobarbital The risk or severity of adverse effects can be increased when Secobarbital is combined with Diphenhydramine. Approved, Vet Approved Secretin human The therapeutic efficacy of Secretin human can be decreased when used in combination with Diphenhydramine. Approved Secretin porcine The therapeutic efficacy of Secretin porcine can be decreased when used in combination with Diphenhydramine. Approved Selegiline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Selegiline. Approved, Investigational, Vet Approved Sennosides The therapeutic efficacy of Sennosides can be decreased when used in combination with Diphenhydramine. Approved Sertindole The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Sertindole. Approved, Investigational, Withdrawn Sertraline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Sertraline. Approved Sevoflurane The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Sevoflurane. Approved, Vet Approved Sibutramine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Sibutramine. Approved, Illicit, Investigational, Withdrawn Sisomicin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Sisomicin. Investigational Sitafloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Sitafloxacin. Experimental, Investigational SLV319 The risk or severity of Tachycardia and drowsiness can be increased when Diphenhydramine is combined with SLV319. Investigational Sodium oxybate Diphenhydramine may increase the central nervous system depressant (CNS depressant) activities of Sodium oxybate. Approved Sodium phosphate, monobasic The therapeutic efficacy of Sodium phosphate, monobasic can be decreased when used in combination with Diphenhydramine. Approved Sodium sulfate The therapeutic efficacy of Sodium sulfate can be decreased when used in combination with Diphenhydramine. Approved, Vet Approved Sodium tartrate The therapeutic efficacy of Sodium tartrate can be decreased when used in combination with Diphenhydramine. Approved Solifenacin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Solifenacin. Approved Sorafenib The risk or severity of QTc prolongation can be increased when Sorafenib is combined with Diphenhydramine. Approved, Investigational Sorbitol The therapeutic efficacy of Sorbitol can be decreased when used in combination with Diphenhydramine. Approved Sotalol The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Sotalol. Approved Sparfloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Sparfloxacin. Approved, Investigational St. John's Wort The risk or severity of adverse effects can be increased when Diphenhydramine is combined with St. John's Wort. Approved, Investigational, Nutraceutical Stiripentol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Stiripentol. Approved Streptomycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Streptomycin. Approved, Vet Approved Styramate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Styramate. Experimental Succinylcholine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Succinylcholine. Approved Sufentanil The risk or severity of adverse effects can be increased when Sufentanil is combined with Diphenhydramine. Approved, Investigational Sulfamethoxazole The risk or severity of QTc prolongation can be increased when Sulfamethoxazole is combined with Diphenhydramine. Approved Sulfisoxazole The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Sulfisoxazole. Approved, Vet Approved Sulpiride Diphenhydramine may increase the anticholinergic activities of Sulpiride. Approved, Investigational Sulthiame The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Sulthiame. Experimental Sultopride The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Sultopride. Experimental Sumatriptan The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Sumatriptan. Approved, Investigational Sunitinib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Sunitinib. Approved, Investigational Surinabant The risk or severity of Tachycardia and drowsiness can be increased when Diphenhydramine is combined with Surinabant. Investigational Suvorexant Diphenhydramine may increase the central nervous system depressant (CNS depressant) activities of Suvorexant. Approved, Investigational Tacrine The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Tacrine. Investigational, Withdrawn Tafenoquine The metabolism of Tafenoquine can be decreased when combined with Diphenhydramine. Approved, Investigational Talbutal The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Talbutal. Approved, Illicit Talinolol The metabolism of Talinolol can be decreased when combined with Diphenhydramine. Investigational Talopram The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Talopram. Experimental Tamoxifen The serum concentration of the active metabolites of Tamoxifen can be reduced when Tamoxifen is used in combination with Diphenhydramine resulting in a loss in efficacy. Approved Tandospirone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tandospirone. Investigational Tandutinib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Tandutinib. Investigational Tapentadol Tapentadol may increase the central nervous system depressant (CNS depressant) activities of Diphenhydramine. Approved Tasimelteon The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tasimelteon. Approved, Investigational Technetium Tc-99m ciprofloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Technetium Tc-99m ciprofloxacin. Investigational Technetium Tc-99m tilmanocept Diphenhydramine may decrease effectiveness of Technetium Tc-99m tilmanocept as a diagnostic agent. Approved, Investigational Tegaserod The therapeutic efficacy of Tegaserod can be decreased when used in combination with Diphenhydramine. Approved, Investigational, Withdrawn Telavancin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Telavancin. Approved Telithromycin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Telithromycin. Approved Temafloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Temafloxacin. Withdrawn Temazepam The risk or severity of adverse effects can be increased when Temazepam is combined with Diphenhydramine. Approved, Investigational Terbutaline The risk or severity of QTc prolongation can be increased when Terbutaline is combined with Diphenhydramine. Approved Terfenadine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Terfenadine. Approved, Withdrawn Terlipressin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Terlipressin. Approved, Investigational Terodiline The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Terodiline. Experimental Tertatolol The metabolism of Tertatolol can be decreased when combined with Diphenhydramine. Experimental Tetrabenazine The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Tetrabenazine. Approved, Investigational Tetracycline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tetracycline. Approved, Vet Approved Tetraethylammonium The serum concentration of Tetraethylammonium can be increased when it is combined with Diphenhydramine. Experimental, Investigational Tetrahydropalmatine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tetrahydropalmatine. Investigational Tetrazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tetrazepam. Experimental Tetrodotoxin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tetrodotoxin. Investigational Thalidomide Diphenhydramine may increase the central nervous system depressant (CNS depressant) activities of Thalidomide. Approved, Investigational, Withdrawn Thiamylal The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Thiamylal. Approved, Vet Approved Thiazinam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Thiazinam. Experimental Thiethylperazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Thiethylperazine. Withdrawn Thiocolchicoside The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Thiocolchicoside. Approved, Investigational Thiopental The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Thiopental. Approved, Vet Approved Thiopropazate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Thiopropazate. Experimental Thioproperazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Thioproperazine. Approved Thioridazine The serum concentration of Thioridazine can be increased when it is combined with Diphenhydramine. Approved, Withdrawn Thiothixene The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Thiothixene. Approved Thonzylamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Thonzylamine. Approved Tiagabine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tiagabine. Approved, Investigational Tianeptine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tianeptine. Approved, Investigational Tiapride The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tiapride. Approved, Investigational Tiemonium iodide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tiemonium iodide. Experimental Tigecycline The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tigecycline. Approved Tiletamine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tiletamine. Vet Approved Tilidine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tilidine. Experimental Timepidium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Timepidium. Experimental Timolol The metabolism of Timolol can be decreased when combined with Diphenhydramine. Approved Tiotropium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tiotropium. Approved Tizanidine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tizanidine. Approved, Investigational Tobramycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tobramycin. Approved, Investigational Tofisopam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tofisopam. Approved Tolcapone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tolcapone. Approved, Withdrawn Toloxatone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Toloxatone. Approved Tolperisone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tolperisone. Approved, Investigational Tolterodine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tolterodine. Approved, Investigational Topiramate The risk or severity of hyperthermia and oligohydrosis can be increased when Diphenhydramine is combined with Topiramate. Approved Toremifene The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Toremifene. Approved, Investigational Tramadol The therapeutic efficacy of Tramadol can be decreased when used in combination with Diphenhydramine. Approved, Investigational Tramiprosate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tramiprosate. Investigational Tranylcypromine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tranylcypromine. Approved, Investigational Trazodone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Trazodone. Approved, Investigational Treprostinil The risk or severity of QTc prolongation can be increased when Treprostinil is combined with Diphenhydramine. Approved, Investigational Triazolam The risk or severity of adverse effects can be increased when Triazolam is combined with Diphenhydramine. Approved, Investigational Tricaine methanesulfonate The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tricaine methanesulfonate. Vet Approved Trichlorfon The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Trichlorfon. Vet Approved Trichlormethiazide The serum concentration of Trichlormethiazide can be increased when it is combined with Diphenhydramine. Approved, Vet Approved Trichloroethylene The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Trichloroethylene. Approved Triclofos The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Triclofos. Withdrawn Tridihexethyl The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tridihexethyl. Withdrawn Trifluoperazine The risk or severity of adverse effects can be increased when Trifluoperazine is combined with Diphenhydramine. Approved, Investigational Trifluperidol The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Trifluperidol. Experimental Triflupromazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Triflupromazine. Approved, Vet Approved Trihexyphenidyl The risk or severity of adverse effects can be increased when Trihexyphenidyl is combined with Diphenhydramine. Approved Trimebutine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Trimebutine. Approved Trimethadione The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Trimethadione. Approved Trimethaphan The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Trimethaphan. Approved, Investigational Trimethoprim The risk or severity of QTc prolongation can be increased when Trimethoprim is combined with Diphenhydramine. Approved, Vet Approved Trimipramine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Trimipramine. Approved Triprolidine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Triprolidine. Approved Triptorelin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Triptorelin. Approved, Vet Approved Tropatepine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Tropatepine. Experimental Tropicamide The risk or severity of adverse effects can be increased when Tropicamide is combined with Diphenhydramine. Approved, Investigational Trospium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Trospium. Approved Trovafloxacin The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Trovafloxacin. Approved, Investigational, Withdrawn Tubocurarine The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Tubocurarine. Approved Tucidinostat The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Tucidinostat. Investigational Tyrothricin The therapeutic efficacy of Diphenhydramine can be decreased when used in combination with Tyrothricin. Approved Umeclidinium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Umeclidinium. Approved Valerian The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Valerian. Approved, Experimental, Investigational Valnoctamide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Valnoctamide. Investigational Valproic Acid The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Valproic Acid. Approved, Investigational Valpromide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Valpromide. Experimental Vancomycin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Vancomycin. Approved Vandetanib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Vandetanib. Approved Vardenafil The risk or severity of QTc prolongation can be increased when Vardenafil is combined with Diphenhydramine. Approved Varenicline Diphenhydramine may decrease the excretion rate of Varenicline which could result in a higher serum level. Approved, Investigational Vecuronium The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Vecuronium. Approved Vemurafenib The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Vemurafenib. Approved Venlafaxine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Venlafaxine. Approved Veralipride The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Veralipride. Experimental Vigabatrin The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Vigabatrin. Approved Vilanterol The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Vilanterol. Approved Vilazodone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Vilazodone. Approved Viloxazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Viloxazine. Approved, Investigational, Withdrawn Vinbarbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Vinbarbital. Experimental Vinpocetine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Vinpocetine. Investigational Vinyl ether The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Vinyl ether. Experimental Vinylbital The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Vinylbital. Experimental Voriconazole The risk or severity of QTc prolongation can be increased when Voriconazole is combined with Diphenhydramine. Approved, Investigational Vorinostat The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Vorinostat. Approved, Investigational Vortioxetine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Vortioxetine. Approved, Investigational WIN 55212-2 The risk or severity of Tachycardia and drowsiness can be increased when Diphenhydramine is combined with WIN 55212-2. Experimental XP19986 The risk or severity of adverse effects can be increased when Diphenhydramine is combined with XP19986. Investigational Xylazine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Xylazine. Vet Approved Zaleplon The risk or severity of adverse effects can be increased when Zaleplon is combined with Diphenhydramine. Approved, Illicit, Investigational Ziconotide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Ziconotide. Approved Zimelidine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Zimelidine. Withdrawn Ziprasidone The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Ziprasidone. Approved Zolazepam The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Zolazepam. Vet Approved Zolmitriptan The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Zolmitriptan. Approved, Investigational Zolpidem Diphenhydramine may increase the central nervous system depressant (CNS depressant) activities of Zolpidem. Approved Zonisamide The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Zonisamide. Approved, Investigational Zopiclone The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Zopiclone. Approved Zotepine The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Zotepine. Approved, Investigational, Withdrawn Zuclopenthixol The risk or severity of QTc prolongation can be increased when Diphenhydramine is combined with Zuclopenthixol. Approved, Investigational - Food Interactions
- Avoid alcohol.
- Take with food.
References
- Synthesis Reference
Alison B. Lukacsko, Joseph J. Piala, "Effect of a combination of a terbutaline, diphenhydramine and ranitidine composition on gastrointestinal injury produced by nonsteroidal anti-inflammatory compositions." U.S. Patent US5260333, issued December, 1983.
US5260333- General References
- Raphael GD, Angello JT, Wu MM, Druce HM: Efficacy of diphenhydramine vs desloratadine and placebo in patients with moderate-to-severe seasonal allergic rhinitis. Ann Allergy Asthma Immunol. 2006 Apr;96(4):606-14. [PubMed:16680933]
- Abdi A, Rose E, Levine M: Diphenhydramine overdose with intraventricular conduction delay treated with hypertonic sodium bicarbonate and i.v. lipid emulsion. West J Emerg Med. 2014 Nov;15(7):855-8. doi: 10.5811/westjem.2014.8.23407. Epub 2014 Sep 19. [PubMed:25493135]
- Halpert AG, Olmstead MC, Beninger RJ: Mechanisms and abuse liability of the anti-histamine dimenhydrinate. Neurosci Biobehav Rev. 2002 Jan;26(1):61-7. [PubMed:11835984]
- Jaju BP, Wang SC: Effects of diphenhydramine and dimenhydrinate on vestibular neuronal activity of cat: a search for the locus of their antimotion sickness action. J Pharmacol Exp Ther. 1971 Mar;176(3):718-24. [PubMed:4329456]
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- Wikipedia
- Diphenhydramine
- ATC Codes
- D04AA33 — Diphenhydramine methylbromide
- D04AA — Antihistamines for topical use
- D04A — ANTIPRURITICS, INCL. ANTIHISTAMINES, ANESTHETICS, ETC.
- D04 — ANTIPRURITICS, INCL. ANTIHISTAMINES, ANESTHETICS, ETC.
- D — DERMATOLOGICALS
- D04AA — Antihistamines for topical use
- D04A — ANTIPRURITICS, INCL. ANTIHISTAMINES, ANESTHETICS, ETC.
- D04 — ANTIPRURITICS, INCL. ANTIHISTAMINES, ANESTHETICS, ETC.
- D — DERMATOLOGICALS
- R06AA — Aminoalkyl ethers
- R06A — ANTIHISTAMINES FOR SYSTEMIC USE
- R06 — ANTIHISTAMINES FOR SYSTEMIC USE
- R — RESPIRATORY SYSTEM
- AHFS Codes
- 04:04.04 — Ethanolamine Derivatives
- 04:04.00 — First Generation Antihistamines
- PDB Entries
- 2aot
- MSDS
- Download (73.5 KB)
Clinical Trials
- Clinical Trials
Pharmacoeconomics
- Manufacturers
- Not Available
- Packagers
- Advance Pharmaceutical
- Advent Pharmaceuticals Inc.
- Amend
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- A-S Medication Solutions LLC
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- Barr Pharmaceuticals
- Baxter International Inc.
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- Dispensing Solutions
- Diversified Healthcare Services Inc.
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- Major Pharmaceuticals
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- Mississippi State Dept Health
- Murfreesboro Pharmaceutical Nursing Supply
- Nexgen Pharma Inc.
- North Safety Products
- Nucare Pharmaceuticals Inc.
- Patient First Corp.
- PCA LLC
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- Perrigo Co.
- Pfizer Inc.
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- Tya Pharmaceuticals
- UDL Laboratories
- United Research Laboratories Inc.
- Vangard Labs Inc.
- Walgreen Co.
- Dosage forms
Form Route Strength Capsule; kit Oral Cream Topical 20 mg/mL Cream Topical 2 mL/100mL Powder Oral 25 mg/1 Liquid Oral 12.5 mg Tablet, chewable Oral 12.5 mg/1 Tablet, film coated Oral 25 mg/1 Solution Oral 12.5 mg Gel Topical 2 g/100g Cream Topical 2.0 % Patch Topical Kit Tablet Oral 25 mg Tablet, coated Oral 25 mg/1 Tablet, chewable Oral 12.5 mg Liquid Topical Liquid Oral 6.25 mg Cream Topical 2 % Elixir Oral 12.5 mg Gel Topical 20 mg/mL Tablet, chewable Oral 25 mg Gel Topical 2 % Tablet Oral 25 mg/250mg Strip Oral 25 mg Lotion Topical Suspension Topical Syrup Oral 6.25 mg Tablet Oral 19 mg Strip Oral 19 mg Suspension Oral Tablet Oral 12.5 mg/1 Liquid Oral 12.5 mg/5mL Kit; tablet Oral Ointment Topical Kit Topical Kit Oral Tablet Oral 38.0 mg Capsule, coated Oral 25 mg/1 Injection, solution Intravenous 50 mg/mL Capsule, liquid filled Oral 20 mg/1 Capsule, gelatin coated Oral 25 mg/1 Liquid Intravenous 50 mg Elixir Oral 12.5 mg/5mL Elixir Oral 25 mg/10mL Injection Intramuscular 50 mg/mL Injection Intramuscular; Intravenous 50 mg/mL Injection, solution Intramuscular; Intravenous 50 mg/mL Solution Oral 25 mg/10mL Solution Oral 50 mg/20mL Liquid Intramuscular; Intravenous 50 mg Kit Oral; Topical Tablet Oral Tablet, film coated Oral Liquid Oral 50 mg/30mL Solution Oral 50 mg/40mL Kit Oral Aerosol, spray Topical Capsule, coated Oral Tablet, coated Oral Powder Oral Capsule, liquid filled Oral Liquid Topical 20.3 g/L Spray Topical 2 g/100mL Gel Topical 2.03 g/100g Aerosol Topical Solution Topical Gel Topical 2 g/100mL Strip Oral 12.5 mg Tablet Oral 12.5 mg Tablet, orally disintegrating Oral 12.5 mg/1 Liniment Topical Cream Topical Capsule, gelatin coated Oral 50 mg/1 Kit Lozenge Oral 25 mg Strip Oral Tablet Oral 50 mg/1 Capsule Oral 25 mg Solution Oral 50 mg Capsule Oral 50 mg/1 Tablet, film coated Oral 50 mg/1 Capsule, liquid filled Oral 50 mg/21 Solution Oral Tablet Oral 50 mg Capsule Oral Capsule, gelatin coated Oral Elixir Oral 2.5 mg Syrup Oral 12.5 mg/5mL Gel Topical 20.5 mg/mL Spray Topical Liquid Oral Plaster Topical Solution Intramuscular; Intravenous 50 mg Gel Topical .2 g/10mL Capsule, liquid filled Oral 50 mg/1 Capsule, liquid filled Oral 25 mg/1 Tablet Oral 25 mg/1 Tablet, coated Oral 50 mg/1 Gel Topical Gel Topical 20 mg/g Spray Topical 20 mg/mL Powder, for solution Oral Syrup Oral Capsule Oral 25 mg/1 Solution Oral 50 mg/30mL Capsule Oral 50 mg Tablet, chewable Oral 25 mg/1 Liquid Oral 6.25 mg/mL Solution Oral 12.5 mg/5mL Liquid Oral 25 mg/10mL Capsule, gelatin coated Oral 50 mg/21 Granule, for solution Oral Spray Topical 2.0 % Liquid Oral 50 mg - Prices
Unit description Cost Unit DiphenhydrAMINE HCl 100 50 mg capsule Bottle 13.99USD bottle Diphenhydramine 50 mg/ml 3.94USD ml Diphenhydramine 50 mg/ml vial 1.69USD ml DiphenhydrAMINE HCl 50 mg/ml vial 1.44USD vial Dytan 25 mg tablet chewable 1.37USD tablet Benadryl 50 mg/ml vial 1.36USD ml Diphenmax 25 mg tablet 1.24USD tablet Benadryl allergy 25 mg strips 0.45USD strip Unisom sleep aid tablet 0.34USD tablet Sleep-eze 3 tablet 0.29USD tablet Compoz 50 mg tablet 0.27USD tablet Sominex max str 50 mg caplet 0.27USD caplet Benadryl allergy fastmelt tablet 0.26USD tablet Unisom 25 mg sleeptabs 0.25USD tablet Unisom 50 mg sleepgels 0.25USD each Unisom sleepmelts 25 mg tablet 0.24USD tablet Nytol 25 mg tablet 0.23USD tablet Benadryl allergy-sinus caplet 0.22USD caplet Compoz 25 mg gelcap 0.2USD capsule Benadryl allergy 25 mg softgel 0.19USD softgel capsule Benadryl allergy 25 mg ultratab 0.19USD tablet Benadryl allergy-cold kapgels 0.19USD each Benadryl allergy-sinus kapgels 0.19USD each Benadryl-d allergy-sinus ultratab 0.19USD tablet Diphenhydramine hcl powder 0.17USD g Eql allergy 25 mg tablet 0.17USD tablet Nighttime sleep aid 25 mg cplt 0.17USD caplet Banophen anti-itch 2% cream 0.16USD g Benadryl itch relief stick 0.16USD ml Sominex 25 mg tablet 0.16USD tablet Benadryl allergy 25 mg kapgels 0.15USD each Allergy 25 mg tablet 0.14USD tablet Benadryl 25 mg kapseals 0.14USD each Benadryl itch stopping crm 0.14USD g DiphenhydrAMINE HCl 25 mg capsule 0.13USD capsule Diphenhist with zinc cream 0.12USD g Ra allergy 25 mg tablet 0.12USD tablet CVS Pharmacy allergy 25 mg tablet 0.11USD tablet Diphenhydramine 25 mg minitab 0.11USD tablet Simply sleep 25 mg caplet 0.11USD caplet Sleep ii tablet 0.11USD tablet Diphenhydramine 50 mg capsule 0.1USD capsule Benadryl 2% spray 0.09USD ml Diphenhist 50 mg tablet 0.09USD tablet Genahist 25 mg tablet 0.09USD tablet Ra sleep tablet 0.09USD tablet Banophen 25 mg tablet 0.08USD tablet Wal-dryl anti-itch spray 0.08USD ml CVS Pharmacy allergy 25 mg caplet 0.07USD caplet Nighttime sleep aid 25 mg caplet 0.07USD caplet CVS Pharmacy itch relief spray 0.06USD ml Diphen 25 mg capsule 0.06USD capsule Diphenhist 25 mg caplet 0.06USD caplet Benadryl anti-itch 0.45% gel 0.05USD g Diphenhydramine 50 mg caplet 0.05USD caplet Benadryl itch stopping gel 0.04USD g Child benadryl-d aller-sin liquid 0.04USD ml Diphenhydramine 25 mg capsule 0.04USD capsule Vicks 44d cough & head liquid 0.03USD ml Vicks 44e cough & chest liquid 0.03USD ml Banophen allergy liquid 0.02USD ml Diphenhydramine 25 mg tablet 0.02USD tablet Ra anti-tussive dm syrup 0.02USD ml Siladryl 12.5 mg/5 ml liquid 0.02USD ml Silphen cough syrup 0.02USD ml Silphen dm cough syrup 0.02USD ml DrugBank does not sell nor buy drugs. Pricing information is supplied for informational purposes only.- Patents
Patent Number Pediatric Extension Approved Expires (estimated) US8883849 No 2002-01-17 2022-01-17 US US9155718 No 2002-01-17 2022-01-17 US US8263647 No 2002-05-30 2022-05-30 US
Properties
- State
- Solid
- Experimental Properties
Property Value Source melting point (°C) 161-162 Martin, H., Hafliger, F.,Gatzi, K.and Grob, A.; U.S. Patent 2,397,799; April 2,1946; assigned to J.R. Geigy AG, Switzerland. Rieveschl, G. Jr.; U.S. Patent 2,421,714; June 3,1947; assigned to Parke, Davis & Co. Rieveschl, G. Jr.; U.S. Patent 2,427,878; September 23,1947; assigned to Parke, Davis & Company. boiling point (°C) 150-165 °C at 2.00E+00 mm Hg PhysProp water solubility 3060 mg/L (at 37 °C) BEILSTEIN logP 3.27 HANSCH,C ET AL. (1995) pKa 8.98 SANGSTER (1994) - Predicted Properties
Property Value Source Water Solubility 0.0752 mg/mL ALOGPS logP 3.44 ALOGPS logP 3.65 ChemAxon logS -3.5 ALOGPS pKa (Strongest Basic) 8.87 ChemAxon Physiological Charge 1 ChemAxon Hydrogen Acceptor Count 2 ChemAxon Hydrogen Donor Count 0 ChemAxon Polar Surface Area 12.47 Å2 ChemAxon Rotatable Bond Count 6 ChemAxon Refractivity 79.93 m3·mol-1 ChemAxon Polarizability 29.86 Å3 ChemAxon Number of Rings 2 ChemAxon Bioavailability 1 ChemAxon Rule of Five Yes ChemAxon Ghose Filter Yes ChemAxon Veber's Rule Yes ChemAxon MDDR-like Rule No ChemAxon - Predicted ADMET features
Property Value Probability Human Intestinal Absorption + 0.9898 Blood Brain Barrier + 0.9381 Caco-2 permeable + 0.8744 P-glycoprotein substrate Substrate 0.6211 P-glycoprotein inhibitor I Non-inhibitor 0.6632 P-glycoprotein inhibitor II Non-inhibitor 0.8381 Renal organic cation transporter Inhibitor 0.7752 CYP450 2C9 substrate Non-substrate 0.7897 CYP450 2D6 substrate Substrate 0.8919 CYP450 3A4 substrate Substrate 0.6173 CYP450 1A2 substrate Inhibitor 0.8306 CYP450 2C9 inhibitor Non-inhibitor 0.9144 CYP450 2D6 inhibitor Inhibitor 0.8932 CYP450 2C19 inhibitor Non-inhibitor 0.9039 CYP450 3A4 inhibitor Non-inhibitor 0.934 CYP450 inhibitory promiscuity Low CYP Inhibitory Promiscuity 0.7293 Ames test Non AMES toxic 0.9132 Carcinogenicity Non-carcinogens 0.6495 Biodegradation Not ready biodegradable 0.9253 Rat acute toxicity 2.7846 LD50, mol/kg Not applicable hERG inhibition (predictor I) Weak inhibitor 0.536 hERG inhibition (predictor II) Inhibitor 0.6318
Spectra
- Mass Spec (NIST)
- Not Available
- Spectra
Taxonomy
- Description
- This compound belongs to the class of organic compounds known as diphenylmethanes. These are compounds containing a diphenylmethane moiety, which consists of a methane wherein two hydrogen atoms are replaced by two phenyl groups.
- Kingdom
- Organic compounds
- Super Class
- Benzenoids
- Class
- Benzene and substituted derivatives
- Sub Class
- Diphenylmethanes
- Direct Parent
- Diphenylmethanes
- Alternative Parents
- Benzylethers / Trialkylamines / Dialkyl ethers / Organopnictogen compounds / Hydrocarbon derivatives
- Substituents
- Diphenylmethane / Benzylether / Tertiary aliphatic amine / Tertiary amine / Ether / Dialkyl ether / Organic nitrogen compound / Organic oxygen compound / Organopnictogen compound / Hydrocarbon derivative
- Molecular Framework
- Aromatic homomonocyclic compounds
- External Descriptors
- tertiary amino compound, ether (CHEBI:4636) / a small molecule (CPD-10890)
Targets
- Kind
- Protein
- Organism
- Human
- Pharmacological action
- Yes
- Actions
- Antagonist
- General Function
- Histamine receptor activity
- Specific Function
- In peripheral tissues, the H1 subclass of histamine receptors mediates the contraction of smooth muscles, increase in capillary permeability due to contraction of terminal venules, and catecholamin...
- Gene Name
- HRH1
- Uniprot ID
- P35367
- Uniprot Name
- Histamine H1 receptor
- Molecular Weight
- 55783.61 Da
References
- Chen X, Ji ZL, Chen YZ: TTD: Therapeutic Target Database. Nucleic Acids Res. 2002 Jan 1;30(1):412-5. [PubMed:11752352]
- Piao H, Nagai S, Tsurumaki T, Niki T, Higuchi H: Potentiation by neuropeptide Y of histamine H1 receptor-mediated contraction in rat blood vessels. Vascul Pharmacol. 2007 Apr;46(4):260-70. Epub 2006 Oct 27. [PubMed:17169617]
- Kesiova M, Alexandrova A, Yordanova N, Kirkova M, Todorov S: Effects of diphenhydramine and famotidine on lipid peroxidation and activities of antioxidant enzymes in different rat tissues. Pharmacol Rep. 2006 Mar-Apr;58(2):221-8. [PubMed:16702624]
- Hasala H, Moilanen E, Janka-Junttila M, Giembycz MA, Kankaanranta H: First-generation antihistamines diphenhydramine and chlorpheniramine reverse cytokine-afforded eosinophil survival by enhancing apoptosis. Allergy Asthma Proc. 2007 Jan-Feb;28(1):79-86. [PubMed:17390763]
- Wang Z, Woolverton WL: Self-administration of cocaine-antihistamine combinations: super-additive reinforcing effects. Eur J Pharmacol. 2007 Feb 28;557(2-3):159-60. Epub 2006 Dec 1. [PubMed:17196194]
- Ishikawa T, Takechi K, Rahman A, Ago J, Matsumoto N, Murakami A, Kamei C: Influences of histamine H1 receptor antagonists on maximal electroshock seizure in infant rats. Biol Pharm Bull. 2007 Mar;30(3):477-80. [PubMed:17329841]
- Havas TE, Cole P, Parker L, Oprysk D, Ayiomamitis A: The effects of combined H1 and H2 histamine antagonists on alterations in nasal airflow resistance induced by topical histamine provocation. J Allergy Clin Immunol. 1986 Nov;78(5 Pt 1):856-60. [PubMed:2878016]
- Kind
- Protein
- Organism
- Human
- Pharmacological action
- Unknown
- Actions
- Antagonist
- General Function
- G-protein coupled acetylcholine receptor activity
- Specific Function
- The muscarinic acetylcholine receptor mediates various cellular responses, including inhibition of adenylate cyclase, breakdown of phosphoinositides and modulation of potassium channels through the...
- Gene Name
- CHRM2
- Uniprot ID
- P08172
- Uniprot Name
- Muscarinic acetylcholine receptor M2
- Molecular Weight
- 51714.605 Da
References
- Liu H, Zheng Q, Farley JM: Antimuscarinic actions of antihistamines on the heart. J Biomed Sci. 2006 May;13(3):395-401. [PubMed:16453179]
Enzymes
- Kind
- Protein
- Organism
- Human
- Pharmacological action
- Unknown
- Actions
- SubstrateInhibitor
- General Function
- Steroid hydroxylase activity
- Specific Function
- Responsible for the metabolism of many drugs and environmental chemicals that it oxidizes. It is involved in the metabolism of drugs such as antiarrhythmics, adrenoceptor antagonists, and tricyclic...
- Gene Name
- CYP2D6
- Uniprot ID
- P10635
- Uniprot Name
- Cytochrome P450 2D6
- Molecular Weight
- 55768.94 Da
References
- Hamelin BA, Bouayad A, Drolet B, Gravel A, Turgeon J: In vitro characterization of cytochrome P450 2D6 inhibition by classic histamine H1 receptor antagonists. Drug Metab Dispos. 1998 Jun;26(6):536-9. [PubMed:9616188]
- Zhou SF, Zhou ZW, Yang LP, Cai JP: Substrates, inducers, inhibitors and structure-activity relationships of human Cytochrome P450 2C9 and implications in drug development. Curr Med Chem. 2009;16(27):3480-675. Epub 2009 Sep 1. [PubMed:19515014]
- Preissner S, Kroll K, Dunkel M, Senger C, Goldsobel G, Kuzman D, Guenther S, Winnenburg R, Schroeder M, Preissner R: SuperCYP: a comprehensive database on Cytochrome P450 enzymes including a tool for analysis of CYP-drug interactions. Nucleic Acids Res. 2010 Jan;38(Database issue):D237-43. doi: 10.1093/nar/gkp970. Epub 2009 Nov 24. [PubMed:19934256]
- Drug Interactions: Cytochrome P450 Drug Interaction Table [Link]
- Kind
- Protein
- Organism
- Human
- Pharmacological action
- Unknown
- Actions
- Substrate
- General Function
- Oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen
- Specific Function
- Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally un...
- Gene Name
- CYP1A2
- Uniprot ID
- P05177
- Uniprot Name
- Cytochrome P450 1A2
- Molecular Weight
- 58293.76 Da
References
- Zhou SF, Zhou ZW, Yang LP, Cai JP: Substrates, inducers, inhibitors and structure-activity relationships of human Cytochrome P450 2C9 and implications in drug development. Curr Med Chem. 2009;16(27):3480-675. Epub 2009 Sep 1. [PubMed:19515014]
- Kind
- Protein
- Organism
- Human
- Pharmacological action
- Unknown
- Actions
- Substrate
- General Function
- Steroid hydroxylase activity
- Specific Function
- Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally un...
- Gene Name
- CYP2C9
- Uniprot ID
- P11712
- Uniprot Name
- Cytochrome P450 2C9
- Molecular Weight
- 55627.365 Da
References
- Zhou SF, Zhou ZW, Yang LP, Cai JP: Substrates, inducers, inhibitors and structure-activity relationships of human Cytochrome P450 2C9 and implications in drug development. Curr Med Chem. 2009;16(27):3480-675. Epub 2009 Sep 1. [PubMed:19515014]
- Kind
- Protein
- Organism
- Human
- Pharmacological action
- Unknown
- Actions
- Substrate
- General Function
- Steroid hydroxylase activity
- Specific Function
- Responsible for the metabolism of a number of therapeutic agents such as the anticonvulsant drug S-mephenytoin, omeprazole, proguanil, certain barbiturates, diazepam, propranolol, citalopram and im...
- Gene Name
- CYP2C19
- Uniprot ID
- P33261
- Uniprot Name
- Cytochrome P450 2C19
- Molecular Weight
- 55930.545 Da
References
- Zhou SF, Zhou ZW, Yang LP, Cai JP: Substrates, inducers, inhibitors and structure-activity relationships of human Cytochrome P450 2C9 and implications in drug development. Curr Med Chem. 2009;16(27):3480-675. Epub 2009 Sep 1. [PubMed:19515014]
- Kind
- Protein
- Organism
- Human
- Pharmacological action
- Unknown
- Actions
- Substrate
- General Function
- Steroid hydroxylase activity
- Specific Function
- Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally un...
- Gene Name
- CYP2C18
- Uniprot ID
- P33260
- Uniprot Name
- Cytochrome P450 2C18
- Molecular Weight
- 55710.075 Da
References
- Zhou SF, Zhou ZW, Yang LP, Cai JP: Substrates, inducers, inhibitors and structure-activity relationships of human Cytochrome P450 2C9 and implications in drug development. Curr Med Chem. 2009;16(27):3480-675. Epub 2009 Sep 1. [PubMed:19515014]
- Kind
- Protein
- Organism
- Human
- Pharmacological action
- Unknown
- Actions
- Substrate
- General Function
- Steroid hydroxylase activity
- Specific Function
- Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally un...
- Gene Name
- CYP2B6
- Uniprot ID
- P20813
- Uniprot Name
- Cytochrome P450 2B6
- Molecular Weight
- 56277.81 Da
References
- Zhou SF, Zhou ZW, Yang LP, Cai JP: Substrates, inducers, inhibitors and structure-activity relationships of human Cytochrome P450 2C9 and implications in drug development. Curr Med Chem. 2009;16(27):3480-675. Epub 2009 Sep 1. [PubMed:19515014]
- Kind
- Protein
- Organism
- Human
- Pharmacological action
- Unknown
- Actions
- Substrate
- General Function
- Prostaglandin-endoperoxide synthase activity
- Specific Function
- Converts arachidonate to prostaglandin H2 (PGH2), a committed step in prostanoid synthesis. Involved in the constitutive production of prostanoids in particular in the stomach and platelets. In gas...
- Gene Name
- PTGS1
- Uniprot ID
- P23219
- Uniprot Name
- Prostaglandin G/H synthase 1
- Molecular Weight
- 68685.82 Da
References
- Zhou SF, Zhou ZW, Yang LP, Cai JP: Substrates, inducers, inhibitors and structure-activity relationships of human Cytochrome P450 2C9 and implications in drug development. Curr Med Chem. 2009;16(27):3480-675. Epub 2009 Sep 1. [PubMed:19515014]
Transporters
- Kind
- Protein
- Organism
- Human
- Pharmacological action
- Unknown
- Actions
- Inhibitor
- General Function
- Quaternary ammonium group transmembrane transporter activity
- Specific Function
- Mediates tubular uptake of organic compounds from circulation. Mediates the influx of agmatine, dopamine, noradrenaline (norepinephrine), serotonin, choline, famotidine, ranitidine, histamin, creat...
- Gene Name
- SLC22A2
- Uniprot ID
- O15244
- Uniprot Name
- Solute carrier family 22 member 2
- Molecular Weight
- 62579.99 Da
References
- Urakami Y, Okuda M, Masuda S, Akazawa M, Saito H, Inui K: Distinct characteristics of organic cation transporters, OCT1 and OCT2, in the basolateral membrane of renal tubules. Pharm Res. 2001 Nov;18(11):1528-34. [PubMed:11758759]
- Kind
- Protein
- Organism
- Human
- Pharmacological action
- Unknown
- Actions
- Inhibitor
- General Function
- Secondary active organic cation transmembrane transporter activity
- Specific Function
- Translocates a broad array of organic cations with various structures and molecular weights including the model compounds 1-methyl-4-phenylpyridinium (MPP), tetraethylammonium (TEA), N-1-methylnico...
- Gene Name
- SLC22A1
- Uniprot ID
- O15245
- Uniprot Name
- Solute carrier family 22 member 1
- Molecular Weight
- 61153.345 Da
References
- Urakami Y, Okuda M, Masuda S, Akazawa M, Saito H, Inui K: Distinct characteristics of organic cation transporters, OCT1 and OCT2, in the basolateral membrane of renal tubules. Pharm Res. 2001 Nov;18(11):1528-34. [PubMed:11758759]
- Kind
- Protein
- Organism
- Human
- Pharmacological action
- Unknown
- Actions
- Inhibitor
- General Function
- Symporter activity
- Specific Function
- Sodium-ion dependent, high affinity carnitine transporter. Involved in the active cellular uptake of carnitine. Transports one sodium ion with one molecule of carnitine. Also transports organic cat...
- Gene Name
- SLC22A5
- Uniprot ID
- O76082
- Uniprot Name
- Solute carrier family 22 member 5
- Molecular Weight
- 62751.08 Da
References
- Ohashi R, Tamai I, Nezu Ji J, Nikaido H, Hashimoto N, Oku A, Sai Y, Shimane M, Tsuji A: Molecular and physiological evidence for multifunctionality of carnitine/organic cation transporter OCTN2. Mol Pharmacol. 2001 Feb;59(2):358-66. [PubMed:11160873]
Drug created on June 13, 2005 07:24 / Updated on August 15, 2018 09:48